ISPDS2 - Archive ouverte HAL

23 downloads 0 Views 2MB Size Report
Oct 2, 2018 - ... Zitoune, 50000 Meknes, Morocco. *Author for correspondence: fati.fergani @gmail.com ..... M. Ben Amor*, H. Ezzin. Laboratory of Physics of ...
Materials Materials and and Devices Devices CONFERENCE VOLUME (ISPDS2) Abdelhai Rahmani

To cite this version: Abdelhai Rahmani. Materials Materials and and Devices Devices CONFERENCE VOLUME (ISPDS2). 2017, .

HAL Id: hal-01886229 https://hal.archives-ouvertes.fr/hal-01886229 Submitted on 2 Oct 2018

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Materials and Devices An international research journal CONFERENCE VOLUME

Guest editor Abdelhai RAHMANI Proceedings of the Second International Symposium on Physics of Data Storage (ISPDS2) – Meknes - Morocco

Published by Collaborating Academics http://co-ac.com OAJ Materials and Devices, Vol.2, No3 (2017) ISSN 2495-3911

DOI : 10.23647/ca.md20172012

http://materialsanddevices.co-ac.com ISSN 2495-3911

General informations Materials and Devices is a new journal devoted to all aspects of materials and related devices. It is Open Access and free of charges for authors. Our aim was to create a high quality journal, with a strict peer-review process, and complying with the transparency rules edicted by the DOAJ, COPE,... Materials and Devices publishes several types of articles : - A : regular papers, that should present the results of original research, not published or submitted somewhere else. - L : short papers, written as letters, focusing on one or few particular aspects, representing a very significant progress, for rapid publication. - R : review papers, that presents a summary of results published in literature, on fields covered by the journal. - T : technical papers, on the development of laboratory technics and aparatus relevant to studies on materials and related devices. Such papers will present the details of the designed technics, and an example of application in real condition. - Ur : Unexpected and « negative » results, the journal accepts papers describing unexpected results, or results considered as negative, provided that the original ground arguments are sound, and that a reasonable interpretation can be proposed. Typical examples are : a synthesis process that is generally successful, which aborts in given cases, or give different unexpected but interesting results, results contradicting a theory or a model, etc. The idea to publish such papers is mainly to save time to the scientific community by giving information that is generally not available, except as private communications between researchers. We are happy to announce these innovations : Section T (technical papers) and Ur (Unexpected and « negative » results are original. They correspond to needs in the scientific community. - Conf: conference papers : Finally, Materials and Devices may also publish conference proceedings and conference papers in special volumes. This service is not free, organizers of conference interested should contact the journal to know details.

Aims and scope of the journal The topics covered by the journal are wide, it aims at publishing papers on : - all aspects related to materials, namely according to their chemical formula (oxides, fluorides, carbon compounds, …, organic, inorganic), to their physical properties (conductors, super-conductors, semi-conductors, insulators, dielectrics,...), to their nature (crystalline or amorphous materials, liquid crystals, modulated systems, aperiodic materials, nanomaterials and nanostructured materials)… or environmental type (ecomaterials), or according to some specific applications. Papers on biomaterials, geomaterials, archeomaterials or on studies of ancient materials are also welcome. A particular attention is also paid on environmental studies related with materials. Authors are also encouraged to submit papers on theoretical studies applied to materials, including pure mathematical approaches, physical approaches, models, numerical simulations, etc. - devices in a wide sense. However, concerning Devices, the scope is restricted to those integrating particular materials (for instance memories based on some specific magnetic materials) or category of materials. Papers on all types of such devices are welcome.

OAJ Materials and Devices - I

Policy of the journal

Materials and Devices is an Open Access (*) journal which publishes original, and peer-reviewed papers accessible only via internet, freely for all. Your published article can be freely downloaded, and self archiving of your paper is allowed! We apply « the principles of transparency and best practice in scholarly publishing » as defined by the Committee on Publication Ethics (COPE), the Directory of Open Access Journals (DOAJ), and the Open Access Scholarly Publishers Organization (OASPA). The journal has thus been worked out in such a way as complying with the requirements issued by OASPA and DOAJ in order to apply to these organizations. Evaluation – peer-reviewing : After reception, the paper is sent to two reviewers for evaluation. In case of divergent opinions of reviewers, the editor-in-chief sends the paper to a third reviewer and then gives a final decision based on all reports. Reviewers are asked to reply within three weeks to warranty a fast publication process. Copyright on any article in Materials and Devices is retained by the author(s) under the Creative Commons (Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)), which is favourable to authors. (*) An open access journal means that all content is freely available without charge to the user or his/her institution. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles in this journal without asking prior permission from the publisher or the author. This is in accordance with the BOAI definition of open access.

International editorial board Orientation of the journal, choice of reviewers, special issues, editorial policy, etc, are discussed by the international editorial board.

List of members Algeria Mokhtar BOUDISSA, Professor Researcher, Dpt EBT, ENMC Laboratory, Faculté de Technologie, Université F. Abbas SETIF-1, Sétif 19000 - boudi44 @ yahoo.fr Brazil Paulo T.C. FREIRE, Full professor, Universidade Federal do Ceará, Fortaleza - tarso @ fisica.ufc.br José

DE LOS SANTOS GUERRA, Professor, Instituto de Física, Universidade Federal de Uberlandia (UFU),

Uberlandia – jsantosguerra @ gmail.com Burkina faso Dieudonné Joseph BATHIEBO, Full professor, University of Ouagadougou – [email protected] Canada Zuo-Guang YE, Professor, Simon Fraser University, Burnaby, BC - zye @ sfu.ca Cuba Aimé PELÁIZ BARRANCO, Full professor, Physics Faculty, Havana University - [email protected] Maria SÁNCHEZ, Full professor, Faculty of Physics, University of Havana – maruchy @ fisica.uh.cu Elena VIGIL, Full professor, Physics Fac. - Materials Sc. & Tech. Inst. (IMRE), University of La Habana, and Solar Energy Cathedra Chairperson, Cubasolar-U.H. - evigil @ fisica.uh.cu Czech Republic Ivan GREGORA, Institute of Physics, Czech Academy of Science, Prague - [email protected] Vacláv JANOVEC, emeritus professor, Prague Denmark Heloisa BORDALLO, Associate Professor, Niels Bohr Institute - University of Copenhagen France Patrice BOURSON, Professor, LMOPS Université de Lorraine - Centralesupelec 2 rue E. Belin 57070 Metz [email protected]

OAJ Materials and Devices - II

Alain CLAVERIE,

Research Director,

CEMES/CNRS Toulouse, and private

consultant to several companies (microelectronics, areospace) [email protected] Pierre SAINT-GRÉGOIRE, Full professor, Universities of Toulon and Nîmes, president of Collaborating Academics, https://fr.linkedin.com/in/saint-gregoire-pierre-5bb6372b [email protected] Philippe SCIAU, Senior Scientist, CEMES-CNRS, 29 rue J. marvig, 31055 Toulouse [email protected] Georges ZISSIS, Professor, Université Toulouse 3 - Paul Sabatier; Laboratoire LAPLACE UMR 5213, Toulouse [email protected]

Lukas M. ENG, TU Dresden,

Germany Institute of Applied Physics, and also, Center for Advancing Electronics Dresden -

[email protected] India Amit DAS, doctor, Solid state physics division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 SM YUSUF, Head, Magnetism Section, and Professor at Homi Bhabha National Institute, Solid state physics division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 Israël Gil ROSENMAN, The Henry and Dinah Krongold Chair of Microelectronics, School of Electrical Engineering-Physical Electronics, Faculty of Engineering, Tel Aviv University, Ramat Aviv - [email protected] Italy Luca REBUFFI, X-ray Optics and Spectroscopy Laboratory Supervisor, Elettra-Sincrotrone Trieste S.C.p.A., Trieste [email protected] Japan Emilio J. JUAREZ-PEREZ, Researcher, Energy Materials and Surface Sciences Unit. Okinawa Institute of Science and Technology Graduate University (OIST) 1919-1 Tancha, Onna-son, Okinawa, 904-0495 - [email protected] , http://ej-juarezperez.home.oist.jp/ Kazakhstan Koblandy TURDYBEKOV, Head of the Department of Physics, Karaganda State Technical University, Karaganda [email protected] Mexico A. Guillermo CASTELLANOS-GUZMÁN, Professor-Researcher, DIP CUCEI Universidad de Guadalajara, Guadalajara Jal. - [email protected] Moldova Anatolie SIDORENKO, Director, Institute of Electronic Engineering and Nanotechnologies "D.GHITU" ASM – [email protected], [email protected] Morocco Abdelhai RAHMANI, Professor, Physics Department, Faculty of Sciences, Meknes [email protected] / [email protected] People Republic of China Yang GAN, Professor, Department head, Harbin Institute of Technology, Harbin - - [email protected] Qinghui JIANG, Assoc Professor, State Key Laboratory of Material Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 [email protected] Zhifu LIU, Professor, CAS Key Lab of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences - [email protected] Xiaoyong WEI, Professor, Electronic Materials Research Laboratory (EMRL) Xi’an Jiaotong University, Xi’an 710049 - [email protected] Poland Maria ZAPART, Institute of Physics, Faculty of Production Engineering and Materials Technology, Czestochowa University of Technology - [email protected]

OAJ Materials and Devices - III

Russian Federation Boris DARINSKII, Professor, Voronezh State University, University sq.1, Voronezh 394006 - [email protected] Alexander SIDORKIN, Professor, Voronezh State University, University sq.1, Voronezh 394006 [email protected] Alexander SIGOV, Professor, Head of Condensed Matter Physics Chair, President of the University, Moscow Technological University, Moscow - [email protected] Mikhail SMIRNOV, Professor, Physical Department, St. Petersburg State University - [email protected] Alexander VTYURIN, deputy director, head of Raman spectroscopy group, Kirensky Institute of Physics, Krasnoyarsk [email protected] Senegal Issakha YOUM, Professor, Department of Physics, FST, University Cheikh Anta DIOP de Dakar, Dakar-Fann Singapore Pooi See LEE, Professor, Nanyang Technological University, Singapore, [email protected] South Africa Malik MAAZA, Chair, UNESCO UNISA Africa Chair in Nanosciences, College of Graduate Studies, UNISA, Pretoria, & NANOAFNET, iThemba LABS, National Research Foundation of South Africa, Faure, Western Cape [email protected] , [email protected] Spain Javier PIQUERAS, Professor, Universidad Complutense de Madrid Carmen ARAGÓ, Full Professor, Dpt. Física de Materiales, Universidad Autónoma de Madrid [email protected] Paloma FERNÁNDEZ, Full professor, Department Materials Physics, Fac. of Physics, University Complutense, Madrid [email protected] Togo Kossi NAPO, Professor, UNESCO Chair on Renewable energies, Faculty of Sciences, University of

Lomé -

[email protected] Ukraine Yulian VYSOCHANSKII, Professor, Uzhgorod National University, Uzhgorod - [email protected] United Kingdom James F. SCOTT,

Depts. of Chemistry and Physics, St. Andrews University, St. Andrews, Fife, UK KY16 9ST -

[email protected]: USA Michael D. HAMPTON, Professor, Department of Chemistry, University of Central Florida, Orlando, FL 32816 Alexei GRUVERMAN, Professor of Physics, University of Nebraska-Lincoln - [email protected] Anirudha V. SUMANT, Ph.D., Materials Scientist, Center for Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Ave., Building 440, Room A-127, Argonne, IL 60439 -

[email protected]

, LinkedIn Profile:

http://www.linkedin.com/in/anisumant Editor-in-Chief : Pierre SAINT-GRÉGOIRE (France) – [email protected] --People interested in this project are welcome ! Contact us to submit your proposals, ideas, suggestions, or to get involved in some actions !

OAJ Materials and Devices - IV

Materials and Devices (ISSN 2495-3911) is a new journal, and as such, is not yet indexed. However in future we shall consider as a priority task, to reach a significant impact factor for this journal.

Collaborating Academics NGO Materials and Devices is owned by the non governmental non profit organization COLLABORATING ACAMICS, an international NGO located in France, that works for scientific communication (organization of meetings, workshops, etc) and development of science. During the launching period authors are encouraged to join the NGO Collaborating Academics (admission fee 15€/year) that supports the journal, in order to help reaching financial stability. COLLABORATING ACADEMICS has launched Collaborating Academics – International Press. CAIP is a collaborative project led by academics and scholars. The main idea is to appropriate the scientific edition in its Open Access form, and keep it free as much as possible. These structures base their activities on volunteerism and you are welcome if you are interested in joining us!

To get involved : Register as potential reviewer/reader/author in the site of the journal : http://materialsanddevices.co-ac.com Join Collaborating Academics : http://co-ac.com and propose ideas ! Submit papers ! Submit your paper on line at Contact us at :

http://materialsanddevices.co-ac.com [email protected]

Publisher : COLLABORATING ACADEMICS

French association (loi 1901) registered Nr W343019101 (Préfecture de l’Hérault). No SIRET: 814 883 476 000 16 – APE 9499Z Address : 14, Av Frederic Mistral, 34110 Frontignan, France Contact : + 33 675 64 02 29 – email : [email protected]

Advertising of free/open source softwares Scientists need efficient, robust, reliable operating systems… Use Linux!

OAJ Materials and Devices - V

Advertising of free/open source softwares

Octave LibreOffice https://www.libreoffice.org/ LibreOffice is a powerful office suite – its clean interface and feature-rich tools help you unleash your creativity and enhance your productivity. LibreOffice includes several applications that make it the most powerful Free and Open Source office suite on the market: Writer (word processing), Calc (spreadsheets), Impress (presentations), Draw (vector graphics and flowcharts), Base (databases), and Math (formula editing).

https://www.gnu.org/soft ware/octave/

GNU Octave is a high-level interpreted language, primarily intended for numerical computations. It provides capabilities for the numerical solution of linear and nonlinear problems, and for performing other numerical experiments. It also provides extensive graphics capabilities for data visualization and manipulation. Octave is normally used through its interactive command line interface, but it can also be used to write non-interactive programs. The Octave language is quite similar to Matlab so that most programs are easily portable.

http://www.scilab.org/en Scilab is free and open source software for numerical computation providing a powerful computing environment for engineering and scientific applications. Scilab includes hundreds of mathematical functions. It has a high level programming language allowing access to advanced data structures, 2D and 3-D graphical functions. A large number of functionalities is included in Scilab.

SciDAVis https://csc.fi/web/elmer/elmer

http://www.abinit.org/ ABINIT is a package whose main program allows one to find the total energy, charge density and electronic structure of systems made of electrons and nuclei (molecules and periodic solids) within Density Functional Theory (DFT), using pseudopotentials and a planewave or wavelet basis… learn more in the internet site!

http://scidavis.sourceforge.net/ SciDAVis is a free application for Elmer is an open source multiphysical Scientific Data Analysis and Visualizat simulation software mainly developed by CSC - IT Center for Science (CSC). Elmer development was started 1995 in collaboration with Finnish Universities, research institutes and industry. After its open source publication in 2005, the use and development of Elmer has become international. Elmer includes physical models of fluid dynamics, structural mechanics, electromagnetics, heat transfer and acoustics, for example. These are described by partial differential equations which Elmer solves by the Finite Element Method (FEM).

OAJ Materials and Devices - VI

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Forewords After the success of the First International Symposium on Physics of Data Storage (ISPDS1) in Amiens, France, December 2015, we have been pleased to organize the second International Symposium on Physics of Data Storage (ISPDS2, website: https://ispds2.sciencesconf.org/), on 31Th October & 01-02Th November 2017, in Moulay Ismail University of Meknes, the oldest Imperial city of Morocco. Following the recommendations of ISPDS1, ISPDS2 has been the continuation of a series of conferences that will be rotated between different universities in the world. ISPDS-2 has also hosted conferences with particularly original content dedicated to PhD students and scientists. This second edition ISPDS2 over three days, has permitted to:  Round up specialists in the advanced materials research field (theoretical and experimental),  Discover the scientific community and research in the Moulay Ismail University,  Review to the younger generation today, through various scientific presentations, the evolution of storage memories and their implementation in physics and electronic devices, and the revolution in nanomaterials and nanotechnology and their applications in renewable energy. We would like to thank the members of the Scientific Committee and all the invited speakers, for their support. We recall that the financial support of the symposium was provided largely by The Moulay Ismail University, the Laboratory of Advanced Materials Studies and Applications, the Faculty of Sciences Meknes, the High School of Technology of Meknes, the National High School of Arts and Crafts, Meknes, and other generous National and International Institutions (CNRST-Morocco, AUF, …). We hope that everyone has found in this meeting an important topical interest and a great pleasure on exchanging with the inter-Mediterranean scientific community. Chairman of organizing committee of ISPDS-2 Prof. Abdelhai Rahmani,

ISPDS2 – presentation

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

General Chairs Abdelali RAHMANI Professor of Physics at Faculty of Sciences, Moulay Ismail University, Meknes. Director of Laboratory of Advanced Materials Studies and Applications (LEM2A). Researcher in Functional Nanomaterials and Numerical simulation. Supervision of many theses. Author of Several scientific papers (+45 publications in peer-reviewed journals, Impact Item +96, RG Score 31.08, Reads>350). Mabrouk BENHAMOU Professor at Faculty of Sciences, Meknes, Morocco; Researcher in Theoretical Physics, Statistical Physics, Soft-Condensed Matter Physics, and Biological Systems. Supervision of more than 50 theses; Author of more than four hundred of scientific papers and advanced books; Editor of many International Scientific Journals; Expert to the benefit of several International Scientific Institutions; Member of directory of many National and International Scientific Societies and Recipient of many Awards and Distinctions. Abdelhai RAHMANI Professor of Physics at Faculty of Sciences, Moulay Ismail University of Meknes. Founding Member of Laboratory of Advanced Materials Studies and Applications (LEM2A). President of Advanced Physics Society of Nanomaterials for Energy and Technology (SPANET). Researcher in spectroscopy (X-ray fluorescence, ICP AES, Raman, IR), Functional Nanomaterials and Numerical simulation; Supervision of many theses; Author of Several scientific papers in peer-reviewed journals.

Organizing Committee Abdelhai RAHMANI (Chairman) Abdellah MIR Brahim Fakrach El Moukhtar ZEMMOURI Hassan CHADLI Khalid SBAI Lahsen BOULMANE Mouhcine BENTALEB Younes BENHOURIA Adil Mohammed NASSIR

Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. National High School of Arts and Crafts, Meknes, Morocco. High School of Technology, Khenifra, Morocco. High School of Technology, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Arts and Humanities, Meknes, Morocco.

Students Committee Mourad BOUTAHIR S.A. AIT ABDELKADER Soukaina EL-MOUDNY Mohamed EL BARGHOUTI Maryam DLIMI Amine LACHHEB

Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco.

ISPDS2 – presentation

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Scientific Committee Abdelali DEROUICHE Abdelali RAHMANI Abdelhai RAHMANI Abdelmajid AINANE Ahmed ZAIM Ali OUBELKACEM Célia TAVARES DE SOUSA El Hassan ELKINANI Hassan CHADLI Hicham BOUGHALEB Ismail ESSAOUDI James SCOTT Jean-Louis BANTIGNIES Jean-Louis SAUVAJOUL Laurent ALVAREZ Lahcen BIH Lahcen KHOUCHAF Mabrouk BENHAMOU Miloud RAHMOUNE Mimoun EL MARSSI Mohamed KEROUAD Mohammed FOUAIDY Mohammed FILALI Mourad BOUGHRARA Nadir ALIOUANE Omar OUSSOUADI Patrick HERMET Pierre SAINT-GREGOIRE Rachid AGOUNOUN Rachid SAADANI Tarik AINANE Youssef EL AMRAOUI Youssef TAHRI Yaovi GAGOU

Faculty of Sciences Ben M'sik, Casablanca, Morocco Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. University of Porto, Porto, Portugal. High National School of Arts and Crafts, Meknes, Morocco. Superior School of Technology, Khenifra, Morocco. Faculty of Sciences, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. University of Cambridge, United, Kingdom. University of Montpellier, Montpellier, France. University of Montpellier, Montpellier, France. University of Montpellier, Montpellier, France. Faculty of Sciences, Meknes, Morocco. Institut Mines Telecom, Lille, France. Faculty of Sciences, Meknes, Morocco. High School of Technology, Meknes, Morocco. University of Picardy, Amiens, France. Faculty of Sciences, Meknes, Morocco. Institut de Physique Nucléaire, Orsay France. Faculty of Science Dhar El Mahraz, Fez- Morocco Superior School of Technology, Khenifra, Morocco. Paul Scherrer Institute, Hague, Netherland. Faculty of Sciences, Meknes, Morocco. University of Montpellier 2, Montpellier, France. University of Toulon, Toulon, France. Superior School of Technology, Meknes, Morocco. Superior School of Technology, Meknes, Morocco. Superior School of Technology, Khenifra, Morocco. National High School of Arts and Crafts, Meknes, Morocco. Faculty of Sciences, Meknes, Morocco. University of Picardy, Amiens, France.

Advisory Committee Daoud MEZZANE Mimoun EL MARSSI Yaovi GAGOU Anna CANTALUPPI

UCA-FST, Marrakech, Morocco. UPJV, Amiens, France. UPJV, Amiens, France. UPJV, Amiens, France.

ISPDS2 – presentation

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

COMMUNICATIONS

ISPDS2 – presentation

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Confinement of organic dyes inside carbon nanotubes

Jean-Louis BANTIGNIES

Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS, Université de Montpellier F-34000 Montpellier, France

Abstract: Opto-electronic properties of single-walled carbon nanotubes can be significantly modified by chromophore confinement into their hollow core. This presentation deals with quaterthiophene derivatives encapsulated into nanotubes displaying different diameter distributions. We show that the supramolecular organizations of the confined chromophores depend on the nanocontainer size. The Raman radial breathing mode frequency is monitored by both the number of confined molecules into a nanotube section and the competition between dye/dye and dye/tube wall interactions. The confinement properties lead also to an exaltation of the infrared absorption response in single-walled carbon nanotubes from dye molecule interactions due to a symmetry breaking, allowing us, thanks to the complementarity of DFT calculations and experimental IR spectra to study interactions between both subsystems. Significant electron transfer from the confined molecules to the nanotubes is also reported from Raman investigations. This charge transfer leads to an important enhancement of the photoluminescence intensity by a factor of nearly five depending on the tube diameter. In addition, close to the molecule resonance, the magnitude of the Raman G-band shifts is modified and the intensity loss is amplified, indicating a photo-induced electron transfer. Results are discussed in the frame of electron-phonon coupling. Thus, confinement species into nanotubes allow moving the Fermi level and consequently to monitor their opto-electronic properties.

OAJ Materials and Devices, Vol 2, #3, p 1 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Copper hexacyanoferrate (CuHCF) functionalized SWCNTs for the solid-liquid selective extraction of cesium

Laurent ALVAREZ

Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS, Université de Montpellier F-34000 Montpellier, France

Abstract: Single-walled carbon nanotubes (SWCNTs) are functionalized with copper hexacyanoferrate (CuHCF) nanoparticles to prepare solid substrates for the sorption of cesium ions (Cs+) from liquid outflows. The high mechanical resistance and large electrical conductivity of SWCNTs are associated to the ability of CuHCF nanoparticles to selectively complex Cs + ions in order to achieve membrane-like buckypapers presenting high loading capacity of cesium. The materials are thoroughly characterized using electron microscopy, Raman scattering, X-ray photoelectron spectroscopy and thermogravimetric analyses. Cs sorption isotherms are plotted after having measured the Cs+ concentration by liquid phase ionic chromatography in the solution before and after exposure to the materials. It is found that the total sorption capacity of the material reaches , and that about one third of the sorbed Cs

is selectively complexed in the

CuHCF nanoparticles grafted on SWCNTs. These high values open interesting outlooks in the integration of such materials in devices for the controlled sorption and desorption of these ions.

OAJ Materials and Devices, Vol 2, #3, p 2 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

On the problem of polarization and charges within domain walls in dielectrics

Pierre SAINT-GREGOIRE

University of Toulon, Campus of La Garde – La Valette, 83130 La Garde, France

Abstract: Domain walls (DWs) in crystalline dielectric materials are two-dimensional objects generally arising as due to structural phase transition(s), and are closely related to the symmetry change taking place in the system. In the present paper, we recall the approach of DWs in terms of symmetry breaking on the basis of V. Janovec’s works, and illustrate in some examples how the tensorial properties – and structure of DWs may differ from those of the bulk material. Particular interesting features are the polarization within walls. We consider also the problem of polarization spatial variation within DWs, and the electrical charges carried by them. In continuous approximation, Landau-Guinzburg approach and the theory of symmetry allow replying to these questions. It is known that DWs may carry a global macroscopic polarization if their symmetry group (which is a layer group) is polar. There are several examples of DWs that should carry an electric polarization, and experimental results supporting this conclusion. However, illustrating the approach by chosen school examples of ferroic materials, we show that in all cases, even if the macroscopic polarization within the wall is not symmetry - allowed, there should occur spatial variations of polarization within DWs, and as a consequence anomalies of electrical charges conferring to the DWs particular properties differing from those of the bulk. The approach of DWs in terms of symmetry was developed by V. Janovec et al. in several papers after the initial basic work published as early as 1976 [1-4].

References: [1] V. Janovec, Ferroelectrics 12, 43 (1976). [2] V. Janovec, Ferroelectrics 35, 105 (1981). [3] J. Přívratská and V. Janovec, Ferroelectrics 222, 1999 (2011). [4] V. Janovec and J. Přívratská, Domain structures, in International Tables for Crystallography, Vol. D, edited by A. Authier, Kluwer Academic, Dordrecht, 2003 and references therein.

OAJ Materials and Devices, Vol 2, #3, p 3 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Piezoelectric actuators for fine dynamic tuning of Superconducting RF cavities fundamental mode frequency

Mohammed FOUAIDY

IPN Orsay, 91406 Orsay, France

Abstract: Superconducting RF (SRF) cavities, resonating at frequencies f0 ranging from 88 MHz to 1300MHz, are used as accelerating structures (at large scale) in particle accelerators. These accelerators are applied for fundamental research studies in a broad range of science (nuclear and high energy physics: Spiral2, LHC, FEL: XFEL and high brightness light sources: SOLEIL, neutrons sources: ESS for condensed matter and advanced material R&D). To lower both investment and operation costs of these accelerators, SRF cavities are operated at high accelerating field

with high quality factors

, However, at high

electromagnetic surface fields, Lorentz force induces small deformations (e.g. the SRF cavity wall leading to a frequency shift or cavity detuning

) of

. Piezoelectric actuators,

which are integrated into Fast Active Cold Tuning System, are used for dynamic tuning of the cavity in order to keep

below the resonator bandwidth. This paper addresses the following

items: 1) Basics properties of Piezoelectric Actuators and some applications of PA, 2) Fundamental properties of SRF cavities for accelerators, 3) State of the art of high performance SRF cavities, 4) Use of Piezo-Actuators for Fast Active Cold Tuning System (FACTS) of SRF resonators. The fourth section is devoted to full characterization of piezoelectric actuators at cryogenic temperatures including radiation hardness test with fast neutrons at fluencies in excess of

.

OAJ Materials and Devices, Vol 2, #3, p 4 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Lecture on the anomalous diffusion in Condensed Matter Physics

Mabrouk BENHAMOU

Faculty of Sciences, Moulay Ismail University, Meknes, Morocco

Abstract: Diffusion is a natural or artificial process that governs many phenomena in nature, and enters in various industrial formulations (processed foods agrochemical products, pharmaceutical preparations, personal care goods…). The most known diffusion is the Brownian motion, where the mean-distancedisplacement followed by the tracer (diffusive particle among others) increases as the square-root of time. It is not the case, however, for complex systems, where the diffusion is rather slow, because at small-scale, these media present a heterogeneous structure. This kind of slow motion is called subdiffusion in literature, and the mean-square-displacement reads: , which deviates from the linear dependence on time found for the Brownian motion. Here, the position in time of the random walker, and

accounts for

for the generalized diffusion constant, also called

"fractional diffusion coefficient". We note that the subdiffusion is a characteristic of the crowded system, where the trajectories of their mobile entities are strongly correlated. The above scaling relation is valid for large-times, that is beyond some characteristic time that depends on the specific details of the diffusion process and the structure of the host medium. Generally, a particle is said to be subdiffusive if the condition , for the interval

, is fulfilled (very slow diffusion). This explains why the exponent

must be in

.

The subdiffusive transport is encountered in a variety of systems including the random-walk in fractal structures, fractional-time Brownian motion, living systems, charge carrier transport in amorphous semiconductors, NMR diffusometry on percolation structures, and the motion of a colloid in a polymer network. For example, for diffusion in fractal structures, , where is the random walkdimension (

, where

the fractional-time Brownian motion, faster) diffusion

are the fractal and spectral dimensions, respectively), and for , where

is the Hurst index. Examples of enhanced (or

include tracer particles in vortex arrays in a rotating flow, layered velocity fields,

and Richardson diffusion. The case transport in polymers),

and

refers to superdiffusion (turbulent plasmas, Levy-flights,

, to ballistic diffusion (optical traps), and

(atmospheric turbulence). The subdiffusion or superdiffusion exponent

, to Richardson diffusion is not a universal quantity, but

mainly depends on the nature of elementary constituents. In this conference, we report on recent advances dealt with anomalous diffusion within complex systems within Condensed Matter Physics, from experimental and theoretical points of views.

OAJ Materials and Devices, Vol 2, #3, p 5 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Environmental Electron Microscopy and nanomaterials: case of SiO2 compounds

Lahcen KHOUCHAF

Institut Mines Telecom, Université de Lille, Rue Charles Bourseul, CS10838, 59808, Douai, France

Abstract: This work reports novel Electron Microscopy investigations to perform adapted studies of nanomaterials. Conventional Scanning Electron Microscope (CSEM) is working under high vacuum (about ) in the specimen chamber. This is a great problem to keep the sample under its natural state. On the other hand, there is much interest in introducing the gas environment in the specimen chamber. At low vacuum, depending on the pressure value in the specimen chamber, different names are given in the literature such as Environmental Scanning Electron Microscope (ESEM), LVSEM: Low Vacuum Scanning Electron Microscope, HPSEM: High Pressure Scanning Electron Microscope, VPSEM: Variable Pres-sure Scanning Electron Microscope, CPSEM: Controlled pressure Scanning Electron Microscope and depending on the maximum pressure attainable in the specimen chamber but all these microscopes differ from CSEM by the capability to introduce the gas as an environment unlike high vacuum in CSEM and the use of gaseous detection system such as Gaseous Secondary Electron Detector (GSED). For this reason, to standardize these names, the Gaseous Scanning Electron Microscope (GSEM) was proposed. The first part of this conference speaks about the principle and new development of GSEM technique. The second part shows the application of GSEM and associated techniques to improve the advanced characterization of nanomaterials. Examples given are SiO2 nanomaterials and interfaces between SiO2 nanomaterials and composite materials (polymers and concrete). For example, doping polymers with nano size SiO 2 particles have a great interest for fundamental science as well as for practical technological applications. But the polymers are very sensitive to the electron beam then the experimental conditions must be optimized in order to keep the samples in their natural state. Without this condition, any attempt to propose a real mechanism will collapse. References: [1] L. Khouchaf, The surface skirt in Gaseous Scanning Electron Microscope GSEM, J. Microscopy Research 1, 29 (2013). [2] L. Khouchaf, Gaseous Scanning Electron Microscope (GSEM): Applications and Improvement, Scanning Electron Microscopy, Viacheslav Kazmiruk (Ed.), ISBN: 978-953-51-0092-8, InTech, (2012). [3] L. Khouchaf et C. Mathieu, La Microscopie Electronique à Balayage sous Environnement Gazeux (MEB-EG): Du principe à l’étude optimisée des matériaux, Ouvrage de référence, ISBN: 9782340018068, Ellipses, 264 pages, (2017).

OAJ Materials and Devices, Vol 2, #3, p 6 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

The spectral moment’s method: improvements and applications

Abdelali RAHMANI

Laboratory of Advanced Materials Studies and Applications (LEM2A) Faculty of Sciences, Moulay Ismail University, Meknes, Morocco.

Abstract: In physics one often expresses the solutions of the equations as series. However this representation is absolutely not suitable when considering functions whose structure is a sum of Dirac peaks. In fact, this is the kind of functions that one encounters in quantum mechanics against either the densities of states or system responses. It is also exactly the same problem in the case of continuous systems such as Maxwell's equations or equations of acoustic waves propagation when one discretisizes them on a network to handle computational machine. There is another type of development that is better adapted to such functions: the continued fraction. In fact we will show that a function which is the sum of Dirac peaks can be easily represented as a continued fraction; the elements of the continued fraction are calculated by recursive methods from generalized moments. Let us note that when the system contains a large number of degrees of freedoms (more than 1 million can be treated), as for realistic systems or hyperfine grids, the dynamical matrix/Hamiltonian is very large and its diagonalization fails or requires long computing time. In contrast, the spectral moment’s method allows us to directly compute the responses and Green’s function of very large systems without any diagonalization of these matrices [1,2]. In the first part of this talk, we give the mathematical basis of the spectral moment’s method and its application in physics. Thereafter some examples are given: Dynamical systems (Nanotube/Dyes hybrids and the infrared, Raman and neutron spectra calculations) [3], electronic systems (electronic densities of states and gap calculations) and photonic band gap materials (Maxwell's equations resolution and Green’s function calculation) [4].

References [1] Benoit, C., Royer, E., and Poussigue, G., The Spectral Moments Method, J. Phys.: Condens. Matter 1992, 4, 3125−3152. [2] Rahmani, A., Sauvajol, J.-L., Rols, S., and Benoit, C., Nonresonant Raman Spectrum in Infinite and Finite Single-Wall Carbon Nanotubes, Phys. Rev. B, 2002, 66, 125404. [3] Fergani, F., Chadli, H., Belhboub, A., Hermet, P., and Rahmani, A., Theoretical Study of the Raman Spectra of C 70 Fullerene Carbon Peapods, J. Phys. Chem. C, 2015, 119, 5679−5686. [4] Benoit, C., Computation of the transmissivity in heterogeneous layers, EPJ-APPL PH, 2001, 13(1), pp. 15-21.

OAJ Materials and Devices, Vol 2, #3, p 7 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

History of Data Storage and new systems

Yaovi GAGOU

LPMC, Université de Picardie Jules Verne, 33 rue saint Leu, 80000 Amiens cedex 01

Abstract: Various memory technologies have emerged throughout history. Today, the discovery of new technologies and new materials helped to manufacture memories devices, less bulky, less expensive, less energy-consuming, but always with a larger capacity and higher speed data transfer. Since the discovery of Vinyl records (1912, 1948 and 1970), data storage has evolved. It exploits progressively all physical properties of materials in new technologies through Analog magnetic recording tape (1920) to Optical data recording (CD in 1979 by Phillips and Sony, DVD sold in 1983 and 1990), Magnetic hard drives, DD (1945), DRAM (1990) SDRAM (1995), New nonvolatile storage, HDD, Flash, USB ... (2000) and Alternative technologies memories (2010), deposition of magnetic elements on substrates (1920). Nowadays, with magnetoelectric behavior, where the variation in the magnetic field (induced current) orients the direction of the electrical dipoles and thus leads to write/read data. For magnetic hard drives the speed today reaches

to

. New technologies using giant magneto

resistance properties (GMR) that reach 2TB of memory storage and Resistance switching effect is now also in progress.

OAJ Materials and Devices, Vol 2, #3, p 8 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

SiGe nanocrystals embedded in SiO2 for charge storage applications

Adil CHAHBOUN

FST, Univertsity Abdelmalek Essaadi, B.P. 416, Tangier, Morocco

Abstract: Nanocrystals (NCs) based memories have emerged as a very promising alternative to the continuous floating gate (Fig. 1). Each NC acts as a discrete charge storage node, leading to better charge retention and thus a greater reliability of the device. Tiwari and colleagues [1] proposed the first alternative memory using Si NCs as particles for charge storage. The challenge of these new technological systems is to produce regular NC’s size and inter-distance. In this work, Si1-xGex NCs

embedded in SiO2 or Al2O3 dielectric matrices were

produced by RF sputtering technique. The NCs multilayer systems were characterized by XRD, Raman, and HRTEM. The retention properties were explored and discussed in relation with the growth conditions.

Fig. 1: HRTEM micrographs of SiGeNCs embedded in SiO2 multilayer sample [2].

References: [1] S. Tiwari et al., Appl. Phys. Lett., 68, 1377 (1996). [2] E. Vieira et al., J. Appl. Phys., 111, 104323 (2012).

OAJ Materials and Devices, Vol 2, #3, p 9 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Magneto caloric Materials for Magnetic Refrigeration

Abdelilah BENYOUSSEF

Hassan II Academy of Sciences and Techniques, Rabat, Morocco

Abstract. The possibility of using magnetic refrigeration has become more reliable during the last twenty years, which will enable it to replace conventional refrigeration systems. Such a change is desirable due to the advantages of using the magnetocaloric effect (MCE) for magnetic refrigeration application, thus leading to high refrigeration efficiency, small volume requirement, low cost, environmental friendliness, no noise pollution and better performance. An excellent magnetic refrigerant should have large magnetic entropy change induced by low magnetic field change. MCE has mainly been investigated for bulk crystal and polycrystal materials. However, nanostructured Gd has a different magnetocaloric behavior when compared with the bulk counterparts. The ordering temperature and magnetic entropy changes of alloy thin films could be tuned by changing the alloy's composition. [Gd/Tb] multilayers with the same thickness and concentration of the studied Gd1-xTbx alloy films enables to strongly increase the relative cooling power, and reach values twice as big as from the corresponding alloys. The origin of this change appears to be a combination of interface defects and lower size effects. Thanks to this approach, the variation of entropy can be controlled continuously from the individual properties of its constituting elements. This study opens up new possibilities in the control and optimization of the magnetocaloric effect in magnetic thin films. Recently, ferrite spinels, such as CoFe2O4, MnZnFe2O4, and ZnNiFe2O4, were studied by numerous research groups in the objective to investigate the magnetic and magnetocaloric properties. Zn1−xNixFe2O4 presents an important relative cooling power “RCP” higher than

which

was considered as a recommended parameter for awide temperature range in magnetic refrigeration application. Perovskite ABO3-type manganites with the general formula (

) (

)

(R:

Rare-earth=La, Pr, Nd…, A: Alkali and Alkali-earth metal=Sr, Ca, Ba…) have attracted a great attention due to their colossal magnetoresistance (CMR) and strong MCE. These properties are explained in the framework of the double exchange interaction between the trivalent (Mn 3+) and tetravalent (Mn4+) manganese. The mixture of (La0.7-xNdx)Sr0.3MnO3 (LNSMO) with a small amount of CuO (typically

weight ratio) enables to markedly enhance the magnetocaloric effect.

Density Functional Theory is a Powerful Quantum Mechanics method for the design of new magnetocaloric materials. Indeed, colossal magnetoresistance (CMR) and strong MCE have been predicted for several materials including MnAs and DyNi4Si.

OAJ Materials and Devices, Vol 2, #3, p 10 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Identification of mono- and few-layer graphene films: X-Ray and Raman studies M. Boutahir1,2, B.B. Balogun1,3, J.C.R.E. Oliveira4, C.T. Sousa1, J.P. Araújo1, A.H. Rahmani2, H. Chadli2, A. Rahmani2* 1

IFIMUP and IN – Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal. 2 Advanced Material and Applications Laboratory (LEM2A), University Moulay Ismail, FSM-ESTM, B.P. 11201, Morocco. 3 Department of Physics and Astronomy, Faculty of Physical Sciences, University of Nigeria Nsukka, Enugu State, Nigeria. 4 CFP, Department of Physics Engineering, FEUP, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. * Author for correspondence: [email protected]

Abstract: The development of new technologies and devices based on the unique properties of graphene requires the accurate determination of the number of graphene layers and low cost methods to prepare them. Raman spectroscopy can be used to provide a rapid, precise and nondestructive analysis to determine the number of layers in graphene thin films. First, an improved and inexpensive method was used to prepare mono-, bi-, tri- and few-layers graphene thin films. We have found that increasing the volume of graphene solution used in the vacuum filtration results in more sheets of graphene. The number of graphene layers deposited in the filtration membranes and in Si substrates was determined using Raman spectroscopy. We also used X-ray diffraction (XRD) to compare the patterns from monolayers and few-layers graphene in liquid and in the thin films. In this work, we calculated the nonresonant Raman spectra of graphene films to analyze our experimental results. The first-order resonance Raman scattering mechanisms in graphene was discussed focused on the origin of the G peak, it changes in shape, position and relative intensity as a function of the number of graphene layers. We have found a good agreement to the group theory concerning the number of the Raman-active modes of mono, bi and few-layers. Keywords: Graphene, XRD, Raman Spectroscopy.

OAJ Materials and Devices, Vol 2, #3, p 11 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Dielectric and impedance spectroscopic studies of lead free Ba1xCax(Zr0.1Ti0.9)O3 ferroelectric ceramics A. Neqali1, H. El Kaddoussi3, A. Lahmar2, Y. Gagou2, M. Amjoud1, A. Alimoussa1, E. Choukri1, H. Khimakhim3, M. El Marssi2*, D. Mezzane1 1

LMCN, Faculty of Sciences and Technologies, University Cadi Ayyad Marrakech, Morocco. LPMC, University of Picardie Jules Verne, 33, rue Saint-Leu, 80039 Amiens Cedex, France. 3 LMMA, Faculty of Sciences-Sfax, B.P. 1171, 3000 Sfax, Tunisie. * Author for correspondence: [email protected] 2

Abstract: The lead free ferroelectric ceramics Ba1-xCax(Zr0,1Ti0,9)O 3 (BCZT) perovskite have been prepared using the solid state reaction technique and investigated by impedance spectroscopy. The thermal evolution of the dielectric constant as a function of temperature and frequency shows a deviation from Curie-Weiss's law ((Ɛ'= C / (T-T0)) at temperatures above

for all the

ceramics studied. This result can be characterized as a dielectric anomaly, associated with the effects of the inter-grain interfaces which combine the conduction and polarization process. In addition, the study of the variation of the real and imaginary part of the dielectric constant as a function of frequency at temperatures above

indicates the existence of the two relaxation

processes related to the grain and the grain boundary. Impedance spectroscopy analysis over the frequency range of 1 Hz to 1 MHz illustrated mainly bulk contribution up to

while grain and grain-boundary effects were present above

The study of the impedance diagrams for four different temperatures (

,

,

. and

) suggests that the anomaly present in the dielectric permittivity measurements is associated with the grain boundaries. The thermal evolution of the electrical conductivity ac for all ceramics studied shows an Arrhenius type behavior with a variation of the slope of the line adjusted around the temperature of

,

that is to say a variation of activation energy (Ea) of the conduction mechanism. The obtained Eavalues were attributed to oxygen vacancies and hopping mechanism.

Keywords: BCZT, Dielectric anomaly, Relaxation processes, Impedance spectroscopy, Activation energy, Hopping mechanism.

OAJ Materials and Devices, Vol 2, #3, p 12 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Theoretical and experimental temperature and frequency dependence of the electrical conductivity in the dynamic regime: application to solar cell material p-cuin3se5 S. Amhil1*, L. Essaleh1, E. Choukri1, A. Alimoussa1, Z. Abkhar1, L. Hajji1 Laboratory of condensed Matter and nanostructures (LMCN), Cadi-Ayyad University, Faculty of Sciences and Technology, Marrakech, Morocco. * Author for correspondence: [email protected]

Abstract: In the context to determinate the electrical properties of the disordered semiconducting materials, we have studied the dynamic ac measurements under an electric field by the impedance spectroscopy (IS) technique in a wide range of frequencies between temperatures between

and

the range

. Different

are considered. The frequency dependence of the

conductivity is interpreted in terms of Jonscher’s law: the conductivity,

to

is temperature-dependent parameter and

where

is

is the power exponent usually lies in

. Different theoretical models are advanced to analyze the temperature

dependence of the exponent s in different materials, namely the Correlated Barrier Hopping (CBH), Quantum Mechanical Tunneling (QMT), the non-overlapping small polaron tunneling (NSPT) and the Overlapping Large Polaron tunneling (OLPT) models [1]. Sometimes more than one of these models can be applied in the same sample depending on the temperature and frequency ranges. In this work, we present, for the first time, a method to identify and analyze the dominant conduction mechanism in a specific temperature range already identified from the temperature dependence of dc conductivity. We apply this method for our experimental data obtained in p-CuIn3Se5 (CIS) an important technological material for its applications in solar cell technology [2].

Keywords: Impedance spectroscopy, Semiconducting materials, Electrical conductivity, Overlapping Large Polaron Tunneling (OLPT), Non-overlapping Small Polaron Tunneling (NSPT). References: [1] S.R. Elliott, Adv. Phys., 36, 135-217 (1987). [2] L. Essaleh, G. Marin, S.M. Wasim. A. Alimoussa, and A. Bourial, Superlattices and Microstructures 92, 353-358 (2016).

OAJ Materials and Devices, Vol 2, #3, p 13 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Mechanisms of relaxation and impedance spectroscopy of Ba0.9Sr0.1TiO3 ceramics H. Zaitouni1*, L. Hajji1, Z. Abkhar1, A. Alimoussa1, L. Essaleh1, M. Elmarssi2, D. Mezzane1, E. Choukri1 1

LMCN, FSTG, University Cadi Ayyad, Marrakech, Morocco. LPMC, University of Picardie, Amiens, France. * Author for correspondence: [email protected] 2

Abstract: Ferroelectric ceramics with the composition Sr-doped BaTiO3 (BST) was synthesized using solid state reaction between the corresponding oxides and carbonates. X-Ray diffraction technique (XRD) showed single phase polycrystalline sample with perovskite structure. The dielectric properties and relaxation were analyzed in the temperature-range alternative current in the frequency range temperature shows a normal ferroelectric transition at

. Variation of dielectric constant

, with with

with a weak degree of diffuseness.

The modified Cole-Cole equation is used to describe all contributions to the relaxation mechanism in BST. The analysis of Nyquist plots reveals the presence of tow contributions. The activation energies have been calculated for these contributions.

Keywords: BST, Ferroelectric ceramics, Conductive relaxation process, Dielectric relaxation, Activation energy.

OAJ Materials and Devices, Vol 2, #3, p 14 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effect of synthesis method on the structural and magnetic properties of LA1−YCAY−XAEXMNO3 ceramics S. Ben Moumen1*, D. Mezzane1, M. Amjoud1, L. Hajji1, L. Essaleh1, E. Choukri1, S. Fourcad2, A. Lahmar3, M. El Marssi3, Y. Gagou3 1

Laboratoire de Matière Condensée et Nanostructures (LMCN) Faculté des Sciences et Techniques Gueliz, Université Cadi Ayyad, BP 549, Marrakech, Morocco. 2 Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) Université de Bordeaux, Centre National de la Recherche Scientifique : UPR9048 87 Av du Dr A. Schweitzer 33608 PESSAC CEDEX - France. 3 Laboratoire de Physique de la Matière Condensée (EA 2081) Université de Picardie Jules Verne 33 rue Saint-Leu 80039 Amiens - France.

Abstract: The perovskite manganite with a general formula Re1-xAexMnO3, where Re is a rare earth and Ae is an alkaline earth, has been extensively studied in recent years because of their colossal magnetoresistance (CMR) properties and potential applications in devices. Many studies have shown that the nature of the magnetic ordering with doped manganites depends on the relative concentration of the Mn3+ and Mn4+ ions, Studies showed that deficiency in LA1−YCAY−XAEXMNO3 powder sample lead to an increase of the Curie temperature,

. In this

case, the magnetic and transport properties of manganites can be modified indirectly by changing the ratio (Mn3+/Mn4+) or the structural parameters Mn–O bond length and Mn–O–Mn bond angle. Structural and magnetic properties of small amount of calcium deficiency of polycrystalline manganite have been investigated by X-ray diffraction (XRD) and magnetic measurements. Our synthesized sample has been successfully elaborated. Rietveld refinements of the X-ray diffraction pattern show that our sample is single phase and crystallize in the orthorhombic structure with Pnma space group. Calcium deficiency leads to an increase of the unit cell volume. At high temperature, our material is a paramagnetic and upon cooling it exhibits a paramagnetic ferromagnetic transition.

Keywords: Multiferroics, Sol-gel, Combustion, Perovskite.

OAJ Materials and Devices, Vol 2, #3, p 15 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Electronic and vibrational properties of nitrogen doped single walled carbon nanotubes F. Allali*, A. Elbiyaali, H. Chadli, A. Rahmani Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A) Université MY Ismail, Faculté des Sciences, B.P. 11201, Zitoune, 50000 Meknès, Morocco. * Author for correspondence: [email protected]

Abstract: Since their first observation in 1991 by Iijima, carbon nanotubes have attracted enormous attention of both experimentalists and theoreticians due to their unique properties. In this theoretical work, vibrational and electronic properties of nitrogen doped carbon nanotubes are investigated in the framework of the tight binding theory and using the spectral moment’s method. The electronic density of state and the band gap of infinite length doped single walled carbon nanotubes are calculated as a function of their diameter and chiralities. The energy gap is calculated for different values of the doping concentration. We found that the direct N substitution creates a new band above the Fermi level and leads to n-type semiconductor. The vibrational modes were calculated for different ratios of nitrogen substitution in single walled carbon nanotubes are also calculated. We present the evolution of the Raman spectrum as a function of the diameter and chirality of the nanotube. On the other hand, the effect of the nitrogen concentration on the Raman spectrum is analyzed. The calculated Raman spectra are compared with the experimental results reported in the literature.

Keywords: Carbon nanotube, Doping, Nitrogen, Raman, Density of state, Spectral moment.

OAJ Materials and Devices, Vol 2, #3, p 16 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Numerical study of the crosstalk effects in ultrasonic transducer arrays utilized in medical imaging N. El Atlas1*, A. Bybi2, H. Drissi1 1

LASTIMI-Laboratoire d’Analyse des Systèmes, Traitement d’Information et du Management, ESTS, Morocco. 2 MEAT-Materials Energy Acoustics Team, Ecole Supérieure de Technologie de Salé (ESTS), Morocco. * Author for correspondence: [email protected]

Abstract: The main component in medical imaging systems is the ultrasound probe composed of several ultrasound transducers often arranged in the form of a linear array (1D) or forming a matrix (2D). The major purpose of on-going and future research in this area is to optimize the electroacoustic performance of ultrasound transducer array in order to obtain a high image resolution for more reliable and safe diagnostics. Crosstalk phenomenon in these ultrasonic arrays has a negative impact on their electroacoustic performances. Indeed, when one element of the array is excited, it generates parasitic displacement fields at the radiating surfaces of the adjacent elementary transducers, which changes the directivity of the antenna and decreases the quality of the obtained images. The goal of this work is to investigate the effect of the filling material, of the matching layer and of the backing material on the crosstalk. Therefore, a transducer array composed of seventeen piezoelectric elements made of PZ27 was modelled using tow-dimensional finite element modelling method. Six filling materials with different loss factors were used to highlight the effect of this parameter on the electroacoustic performance of the array. Then, a double matching layer SU8-Epoxy was utilized to resolve the mismatching problem between active elements and the human body. Thereafter, monolayer and multilayer backing absorbers were added in order to study the impact of front and back matching layers on crosstalk phenomenon. In this way, the great influence of the filling material was pointed out. A kerf filler with high loss factor contributes better to the absorption of parasitic modes between elements but a compromise must be done to have a suitable transmitting voltage. It was also demonstrated that the front matching layer is the major source of crosstalk phenomenon and the proposed multilayer backing has shown good results.

Keywords: Piezoelectric array transducer, Finite element modelling method, Matching layer, Kerffiller, Multilayer backing.

OAJ Materials and Devices, Vol 2, #3, p 17 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Prediction of filler-matrix interphase effects on AC and DC electrical conductivities behavior of carbon black-filled polymer nanocomposites. A. Aribou1, Y. Nioua1, I. Bouknaitir1, M. El Hasnaoui1, M.E. Achour1*, L.C. Costa2 1

LASTID Laboratory, Physics Department, Faculty of Sciences, Ibn Tofail University, B.P. 133, 14000, Kénitra, Morocco. 2 I3N and Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal * Author for correspondence: [email protected]

Abstract: This study deals the prediction of conducting filler-matrix interphase effects on electrical conductivity behaviour of two series of samples which are (Raven 2000/DGEBF, Raven7000/DGEBF) composites. In order to consider the interactions between the filler particles and the matrix we introduce the interphase volume fraction as a parameter of the generalized effective medium (GEM) model for AC and DC electrical conductivity. This interphase volume fraction characterizing the boundary of the shaded region between the polymer chains and the conducting particles depends on the filler type and concentration. One output of this model (GEM modified model) is that it allows us to estimate the volume and intrinsic conductivity of the interphase by fitting with experimental data over a broad range of low frequency at room temperature.

Keywords: Polymer, CB particles, Interphase, GEM modified model.

OAJ Materials and Devices, Vol 2, #3, p 18 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Design analysis of composite materials–absorbent medium interface based plasmonic imaging system B. Bouhafs*, M. Bendjebbour, M. Benatallah University of Tlemcen, Faculty of Sciences, Theoretical Physics Laboratory, B.P.119, Tlemcen 13000, Algeria. * Author for correspondence: [email protected], Tel: +213(43) 212495

Abstract: Electromagnetic excitations generated under certain conditions along an interface between a metal and a dielectric, were extensively used for various applications such as molecular interactions, gas detection, etc. The present work reports on the analysis of a composite noble metal-absorbent medium interface based surface plasmon resonance (SPR) sensor. The above interface coating an optical coupler is investigated in angular interrogation with p-polarized light. In a dependent-wavelength, of the excited light, the permittivity, of the active material described as a mixture with dielectric pores, is modelled by the effective medium theory (EMT). In the presence of an absorbing environment whose optical properties are controlled on the concentration, C we investigate the existence of surface electromagnetic modes on both the effects of critical thickness, , of the active material layer, the optical nature of the pores and the porosity, . Thus, based on the transfer matrix method, the numerical study of the reflected power correlated to the confined electromagnetic modes travelling along the adopted interface allows concluding that composite materials have a preference over real materials to design accurate surface plasmon resonance sensors in terms of the resolution essentially recommended in interferometer devices. Therefore, the approach discussed here already shows a promising potential to design a highly sensitive SPR sensor.

Keywords: Composite noble metal, Surface plasmon resonance sensor, Confined electromagnetic modes, Optical resolution.

OAJ Materials and Devices, Vol 2, #3, p 19 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effect of strontium on the structural and electrical properties of the sol gel processed barium titanate A .El Ghandouri*, S. Sayouri Laboratory of Theoretical and Applied Physics, FSDM, B.P. 179, Fez, Morocco. * Author for correspondence: [email protected]

Abstract: In this study, we elaborate a barium titanium ceramics with a great doping concentration of strontium in A-site. Ba1-xSrxTiO3 (

and

) were synthesized by the sol-gel

method. The samples have been characterized by X-ray diffraction (DRX), infrared(IR) and Raman diffraction. Show that all powders of Ba1-xSrxTiO3 ( for

and

), calcined at

hours crystallize in the pure perovkite phase and on the other hand the average crystallite size

calculated by Deby Scherrer’s equation was

. The effect of the Strontiu concentration to the

tetragonality phase formation as pseudo-cubic structure for all samples. The average grain size and other structural parameters were estimated from the XRD patterns. Electrical measurement, at width range of frequencies, indicates a typical phase transition at maxima in temperature with a greatest value of

plots as a function of

. The effect of the Sr concentration to the electrical

properties of the BT matrix was examined using the empirical formulas such as Curie-Weiss law, Power law and Arrhenius law.

Keywords: Sol-Gel, DRX, Raman, Structral properties, Electrical properties.

References: [1] W. Li, Z. Xu, R. Chu, P. Fu, and J. Hao, Structure and electrical properties of BaTiO3 prepared by sol–gel process, Journal of Alloys and Compounds, 482 (2009) 137–140. [2] F. Du, B. Cui, H. Cheng, R. Niu, and Z. Chang. Synthesis, characterization, and dielectric properties of Ba(Ti1xSnx)O3, Materials Research Bulletin, 44 (2009) 1930–1934.

OAJ Materials and Devices, Vol 2, #3, p 20 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Synthesis, structural and dielectric properties of Pb (La Co ) Zr Ti O 0.9

0.75

0.25

1-x

x 0.1

3

H. Lemziouka1,2*, A. Boutahar2, L.H. Omari3, A. Hajjaji2, M. Abid1, H. Lassri3 1

Renewable Energy Laboratory and Dynamic Systems, Faculté des Sciences Ain-Chock, Université Hassan II-Casablanca, Morocco. 2 Laboratoire des Sciences de l’Ingénieur pour l’Energie. Ecole Nationale des Sciences Appliquées d’El Jadida, B.P. 1166, Université Chouaib Doukkali-El Jadida, Plateau 24002, Morocco. 3 LPMMAT, Université Hassan II, Faculté des Sciences Ain-Chock, B.P. 5366, Mâarif-Casablanca, Morocco. * Author for correspondence: [email protected]

Abstract: Pb0.9 (La1-xCox)0.1 Zr0.75 Ti0.25O3 (

and

) perovskite were successfully

synthesized using sol gel method. The effect of cobalt substitution on the structural and dielectric properties has been investigated. X-ray diffraction measurements show that the lattice parameter and the tetragonality decrease with the increase of Co substitution. Moreover, the temperature dependence of dielectric permittivity indicates that the phase transition temperature increases with increasing Co content.

Keywords: Dielectric properties, Sol-gel, Perovskite.

OAJ Materials and Devices, Vol 2, #3, p 21 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effect of MoS2 layer on the LSPR in nanostructures periodicals of silver nanoparticles applications for the sensitive detection of sensors M. El Barghouti1*, A. Mir1, A. Akjouj2 1

Laboratory for the Study of Advanced Materials and Applications (LEM2A), Physics Department, Faculty of science, Moulay Ismail University, B.P. 11201, Zitoune, Meknès, Morocco. 2 Institut d’Electronique, de Microélectronique et de Nanotechnologie, UMR CNRS 8520, Université Lille 1, Sciences et Technologies, Avenue Poincaré – B.P. 60069, 59652 Villeneuve d’Ascq, France. * Author for correspondence: [email protected]

Abstract: In this work, we study the interaction of the silver nanoparticles with thin layers using MoS2 as spacer. Silver is the ideal material for the plasmonic due to its low loss at optical frequencies. MoS2 is used as part of the finer spacing possible with silver nanoparticles, because MoS2 does not interfere with the ability of the localized surface plasmons to interact with the environment of the detecting applications. Among the advantages of the MoS 2 is to protect the nanostructure, avoids oxidation of nanoparticles and improves the sensitivity compared to the uncoated MoS2 LSPR detection system. Present a

higher sensitivity of the AgNPs only

and two improvements in addition to quantities. The variation of the MoS 2 coating layers are the necessary parameters for the system of LSPR proposed to achieve the highest sensitivity of detection range and the good merit factor

(RIU-1).

Keywords: Localized surface plasmon resonance, Silver nanoparticles, MoS2 layer, Sensitivity.

OAJ Materials and Devices, Vol 2, #3, p 22 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Interactions between bare microemulsion droplets: A small-AngleNeutron-Scattering study R. Ahfir, M. Filali* Laboratory of Theoretical and Applied Physics, Sidi Mohammed Ben Abdellah University, Faculty of Science Dhar El Mahraz, B.P. 1796, Atlas, Fez, Morocco. * Author for correspondence: [email protected]

Abstract: In this work, we investigate thermodynamic and structural properties ofbare microemulsion droplets suspended in salt water by using small Angle Neutron Scattering (SANS). First, the study of shape is made, considering the renormalized spectra in Porod representation for all the studied volume fractions

,

,

obtained from the position of themaxima and minimum

and

), the radius can . Second, the interactions

between droplets have been analyzed using the pair correlation function, factor,

, and the structure

, we compute the structure factor with an effective pair potential, using the Ornstein-

Zernicke integral equation approach together with the hypernetted chain (HNC) closure relation. Finally, the study is completed by a presentation of the various thermodynamic quantities; the compressibility, internal energy, chemical potentials, and free energy. A reasonable agreement between experimental data and simulation was found for the range of the wave vector q studied.

Keywords: Structure factor, Pair-correlation function, Bare microemulsion, Small-Angle-NeutronScattering, Ornstein-Zernike, Hypernetted chain.

OAJ Materials and Devices, Vol 2, #3, p 23 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

The magnetocaloric effect of the binary alloy ferromagnetic nanoparticle M. Zaim*, A. Zaim, M. Kerouad Laboratoire de Physique des Matériaux et Modélisation des Systèmes (LP2MS), Unité Associée au CNRSTURAC: 08, Faculty of Sciences, B.P. 11201 Zitoune, Meknes, Morocco. * Author for correspondence: Fax: +212 5 35 45 43 01, [email protected]

Abstract: In this work, the Monte Carlo simulation based on Metropolis algorithm has been used to study of the magnetization behavior and the magnetocaloric effect of a binary alloy ferromagnetic nanoparticle with radius

of the type ApB1-p. The system consists of two different species of

magnetic components, namely, A and B with spins

and

, respectively. The effect

of the concentration of the p atom and the exchange interaction between two atoms A and B on the magnetization and the magnetic entropy change of the system are discussed. It is found the magnetization at low temperature decreases but phase transition from ferromagnetic to paramagnetic decreases, as the concentration of the

atom in the system increases. Moreover, the

specific heat and the susceptibility exhibit peaks at the transition temperature. The thermal magnetic entropy for different external magnetic field and different exchange interactions in the system is obtained.

Keywords: Nanoparticle, Magnetocaloric effect, Monte Carlo simulation.

OAJ Materials and Devices, Vol 2, #3, p 24 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

The blocking temperature of a cylindrical nanowire system N. Zaim*, A. Zaim, M. Kerouad Laboratoire de Physique des Matériaux et Modélisation des Systèmes (LP2MS), Unité Associée au CNRSTURAC: 08, Faculty of Sciences, B.P. 11201 Zitoune, Meknes, Morocco. * Author for correspondence: Fax: +212 5 35 45 43 01, [email protected]

Abstract: The blocking temperature of a cylindrical nanowire with radius R is studied within of the framework of Monte Carlo simulation based on Metropolis algorithm. The nanowire is formed by alternate layers of atoms A and B. The interlayer coupling, exchange couplings

and

, is ferromagnetic. The effects of the

and the transverse anisotropies

and

on the blocking

temperature of the system are investigated. We found that the blocking temperature increases with increasing the value of the exchange couplings anisotropy,

and

and decreases with increasing the

. Whereas, in the case of the increasing the anisotropy

no change of the blocking

temperature is observed.

Keywords: Blocking temperature, Nanowire, Heisenberg model, Monte Carlo simulation.

OAJ Materials and Devices, Vol 2, #3, p 25 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effects of grain size engineering on microstructure and dielectric properties of doped-batio3 lead-free ferroelectric ceramics Z. Hanani1*, M. Amjoud1, D. Mezzane1, S. Fourcade2, B. Asbani1, A. Danine2, M. Gouné2, M. Lahcini3 1

LMCN - FSTM - Cadi Ayyad University, Morocco ICMCB, University of Bordeaux, FranceLCO2MC - FSTM - Cadi Ayyad University, Morocco * Author for correspondence: Tel: +212 602 725 172, [email protected] 2

Abstract: For half a century, lead-based ferroelectric materials, such as Pb(Zr,Ti)O 3 (PZT) have been widely studied as a potential technological materials to fabricate actuators, sensors and transducers [1]. Nevertheless, the high toxicity of lead can pollute environment, cause damage to brain and nervous system [2]. Thus, due to environmental concern and human health, an intensive research has been conducted to find the appropriate alternative to lead-based materials [3]. A promising category of lead-free ceramic is the perovskite barium titanate (BaTiO 3). It is a bioceramic which does not contain any toxic or volatile element, and its properties can be easily tailored by site engineering [4]. However, as compared with lead-based perovskite ceramics such as (PZT), pure BaTiO3 exhibits relatively low dielectric constant

piezoelectric coefficient

.

To overcome this drawback, many efforts were concentrating on doping strategy to modify barium titanate [5]. It is well known that the properties of ferroelectric ceramics are very sensitive to their microstructure. Thus, through a wide understanding of the vital role which plays grain size, it can be easily to enhance the ferroelectric and dielectric properties of lead-free ceramics [6]. In this study, an environmental synthesis route led to design doped-BaTiO 3 materials with a specifically tailored grain size via nanoscale building blocks. As a consequence, enhanced dielectric properties (high dielectric constant and low dielectric loss) were obtained even at low temperature of sintering. Keywords: Lead-free, BaTiO3, Ferroelctric; Dielectric, Relaxor, Microstructure. References: [1] B. Asbani, J.L. Dellis, A. Lahmar, M. Courty, M. Amjoud, Y. Gagou, K. Djellab, D. Mezzane, Z. Kutnjak, and M. El Marssi, Appl. Phys. Lett. 106, 42902 (2015). [2] J. Rödel, K.G. Webber, R. Dittmer, W.Jo, M. Kimura, and D. Damjanovic, J. Eur. Ceram. Soc. 35, 1659 (2015) [3] P.K. Panda and B. Sahoo, Ferroelectrics 474, 128 (2015). [4] B. Luo, X. Wang, Y. Wang, and L. Li, J. Mater. Chem. A 2, 510 (2014). [5] B. Asbani, Y. Gagou, J.L. Dellis, A. Lahmar, M. Amjoud, D. Mezzane, Z. Kutnjak, and M. El Marssi, Solid State Commun. 49, 237–238, (2016). [6] Y. Tan, J. Zhang, Y. Wu, C. Wang, V. Koval, B. Shi, H. Ye, R. McKinnon, G. Viola, and H. Yan, Sci. Rep. 5, 9953 (2015).

OAJ Materials and Devices, Vol 2, #3, p 26 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

The effect of a random transverse field on the critical and compensation behaviours of an antiferroelectric nanowire with core/shell morphology M. Tarnaoui*, A. Zaim, M. Kerouad Laboratoire de Physique des Matériaux et Modélisation des Systèmes (LP2MS), Unité Associée au CNRSTURAC: 08, Faculty of Sciences, B.P. 11201 Zitoune, Meknes, Morocco. * Author for correspondence: Fax: +212 5 35 45 43 01, [email protected]

Abstract: In this works, the effective field theory based on the probability distribution method has been used to study phase diagram of an antiferroelectric nanowire with core/shell morphology in the presence of the random transverse field. This system is studied by using the transverse Ising-model (TIM). We have investigated the effects of the temperature, the concentration of transverse field, the surface shell and interface couplings on the critical and compensation behaviours of the system. The polarization, the susceptibility and the pyroelectric coefficient as a function of the temperature are examined. We have found that, for appropriate values of the system parameters, a compensation point may be obtained in the present systems.

Keywords: Nanowire, Random transverse field, Compensation temperature.

OAJ Materials and Devices, Vol 2, #3, p 27 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

A systematic investigation on conduction process in ferroelectric ceramics of Lithium-niobate materials A. El Bachiri1*, M. El Hasnaoui2*, A. Louardi3, F. Bennani4, L. Soussi5 1

Laboratoire Bio-Géosciences et Ingénierie des Matériaux (LBGIM), Ecole Normale Supérieure, Université Hassan II, B.P. 50069, Casablanca, Morocco. 2 LASTID Laboratory, Physics Department, Faculty of Sciences, B.P. 133, Kenitra, Morocco. 3 LPMC, Faculté des Sciences, Université Chouaib-Doukkali, El Jadida, Morocco. 4 LPMC, Faculté des Sciences, Université Ibn Tofail, B.P. 133, 14000 Kenitra, Morocco. 5 Laboratoire d’Ingénieries des Systèmes Electriques et des Télécommunications, Ecole Nationale des Sciences Appliquées de Kénitra (ENSAK), Morocco. * Author for correspondence: [email protected]

Abstract: Samples of ferroelectric ceramic of Lithium-niobate oxide (LiNbO3) material synthesized by solid-state reaction were investigated. Raman spectra analysis of polycrystalline samples confirmed that the structure of these ceramics became more rigid when the amount of the Li composition increased. Frequency and temperature dependences of dielectric permittivity and electric modulus of these ceramics were studied in the ranges of frequency from to and temperature from 300 to loss

, respectively. We found that the both dielectric consant

and

are high at lower frequencies and decreases with increase in frequency. Furthermore, the

electric modulus analyses reveal a non-Debye relaxation behavior since relaxation frequency moves towards the positive side with increase in temperature. The shift in modulus peaks (Fig. 1) towards higher frequency side indicates a specific conduction process in material and favouring of long range motion of mobile charge carriers. Relaxation frequency extracted using imaginary part of complex modulus and the temperature dependence of the dc conductivity gave evidence of a transport mechanism based on the three dimensional Mott's variable-range hopping. Using this model we were able to calculate meaningful values for the density of states N (EF), hopping distance

and hopping energy

These reveals that

,

(the parameter

α describes the spatial extent of the localized wave function). Hence, these results were found to be consistent with the Mott and Davis requirement for variable range hopping conduction and the density of localized states N (EF).

Fig. 1: Imaginary part of the electric modulus as a function of frequency at different temperatures, case of sample 2, and solid lines are the best fitted curves.

Keywords: Ceramics, Conductivity, Mott’s complex modulus.

OAJ Materials and Devices, Vol 2, #3, p 28 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Ultrasound characterization of the sensitivity to accelerating admixtures type and dosage on setting and hardening of mortar N. Khatib*, E. Ouacha, B. Faiz, M. Ezzaidi Laboratory of Metrology and Information Processing, Ibn Zohr University, Faculty of Sciences, B.P. 8106, Agadir, Morocco. * Corrersponding author: [email protected]

Abstract: The wave propagation methods can be used for quality control in production of concrete and of admixtures. In this study, the possible use of ultrasound pulse echo method in order to continuously monitor setting and hardening of mortar containing different accelerating admixtures for concrete was investigated. The sensitivity to change in accelerator type and dosage were evaluated. The experiments were performed on mortar containing Portland composite cement CPJ 45 produced in the cement plant of Agadir. A single

central frequency transducer is used as a transmitter

and as a receiver of US-signals. The processing and analysis of signals containing echoes reflected on the different boundaries of the container’s media show as the influence of the change in accelerator dosage on the evolution of the US-parameters vs. concrete age.

Keywords: Non-destructive testing, Ultrasound, Pulse echo, Mortar, Acceleration admixtures, Dosage.

OAJ Materials and Devices, Vol 2, #3, p 29 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Synthesis, structural and dielectric properties of SrBi2Nb2O9 M. Afqir1,2*, A. Tachafine2, D. Fasquelle2, M. Elaatmani1, J.-C. Carru2, A. Zegzouti1, M. Daoud1 1

Laboratoire des Sciences des Matériaux Inorganiques et leurs Applications, Faculté des Sciences Semlalia, Université Cadi Ayyad, Marrakech, Morocco. 2 Unité de Dynamique et Structure des Matériaux Moléculaires, Université du Littoral-Côte d’Opale, Calais, France. * Author for correspondence: [email protected]

Abstract: SrBi2Nb2O9 materials belong to the Aurivillius family of bismuth layered perovskite oxides. SrBi2Nb2O9 is a potential candidate for Ferroelectric Random access Memory (FeRAM) applications. SrBi2-xSmxNb2O9

ceramics were prepared through conventional solid

state route. A series of materials have been characterised by XRD. Dielectric and electrical properties of these materials with temperature at different frequencies have been carried out. The results show that the dielectric permittivity and loss tangent were found to decrease with an increasing concentration of samarium. Reaching at

and

Sm3+, relaxor behaviour took

place.

Keywords: Aurivillius, Solid-state, Dielectric properties, Electrical conductivity.

OAJ Materials and Devices, Vol 2, #3, p 30 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

An intercalation experience of polyethylene glycol 6000 into nanoclay sheet of a marl row material I. Akhrif1,2, M. El Jai3*, L. Mesrar1, R. Jabrane1, M. Benhamou4 1

Geoscience & Environment Laboratory, Faculty of Science & Technique, Sidi Mohamed Ben Abdellah University, Fez, Morocco. 2 Civil Engineering Department, Université Privée de Fez, Morocco. 3 Ecole Nationale Supérieure d’Arts et Métiers, Moulay Ismail University, Meknes, Morocco. 4 Faculty of Science, Moulay Ismail University, Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: The purpose of the work lies with the building of clay matrix/polymer nanocomposites using natural marls of Fez region. The ecological constraints and the search of simplicity led us to proceed by a simple experiment protocol based on mixing in water milieu, since the polyethylene glycol 6000 is a water soluble polymer, as presented in the article. Thus, we present an overview on the major findings, using XRD and FTIR analysis. The intercalation analysis is performed according to the comparison with the humid mixing technique adopted and a simple grinding of the two substances. Indeed, by XRD analysis, we could observe the total intercalation of the polymer into the clay sheets and the X-ray radiation absorption increasing according to the polymer fraction. The inter-sheet distance is also measured and will be modelled in a future work. FTIR led us to confirm the possibility of the intercalation of the polymer into nanoclay sheets.

Keywords: Clay/Polymer Nanocomposite elaboration, Intercalation, Physical characterization, XRD, FTIR, Nanoclay intersheet spaces.

OAJ Materials and Devices, Vol 2, #3, p 31 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Magneto-optical Kerr effect in CdTMO2 (TM= Cr and Mn) B. Bennecer*, H. Chibani, A. Hamidani Physics Laboratory at Guelma, Faculty of Mathematics, Computing and Material Sciences, University 8 Mai 1945 Guelma, P.O. Box 401, Guelma 24000, Algeria. * Author for correspondence: Fax: +21337100555, [email protected]

Abstract: First principles generalised gradient full potential density-functional calculations were performed to predict the optical and magneto-optical (MO) properties of the chalcopyrite compounds CdTMO2, TM=Cr and Mn. The optical properties in the

energy range are

analyzed in terms of band structure transitions (Fig. 1). As for the magneto–optical properties, our results show that the studied compounds have peaks in the Kerr rotation ranging from infrared to ultraviolet radiation. The peaks in the Kerr spectra were assigned to the optical and magneto–optic contributions. Our calculated function of merit for these two compounds indicates that these compounds might be useful for technological application in high density storage.

Fig. 1: Kerr spectra for CdCrO2 with GGA+U.

Keywords: Chalcopyrite, Ab initio calculations, Optical conductivity, Magneto-optical properties.

OAJ Materials and Devices, Vol 2, #3, p 32 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Extensive study of cage effect and subdiffusion in Pickering emulsions using Molecular Dynamics simulations S. El-Moudny1*, M. Badia2, M. Benhamou1, M. El Ossmani3 1

Physics Department, Faculty of Sciences, P.O. Box 11201, Moulay Ismail University, Meknes, Morocco. Ecole Royale de l'Air, Département de Mécanique P.O. Box 40002, Menara, Marrakech, Morocco. 3 ENSAM, Moulay Ismail University, Morocco. * Author for correspondence: [email protected] 2

Abstract: In this work, we aim at an extensive study of the diffusion phenomenon of oil-droplets dispersed in water onto which are strongly adsorbed charged point-like particles (Pickering emulsions). This diffusion that originates from multiple collisions with the molecules of water, is anomalous, due to the presence of relatively strong correlations between the moving oil-droplets. Using Molecular Dynamic simulation, with a pair-potential of Sogami-Ise type, we first observe that the random walkers execute a normal diffusion, at intermediate time, followed by a slow diffusion (subdiffusion) we attribute to the presence of cages, formed by the nearest neighbours (traps). In the cage-regime, we find that the mean-square-displacement increases according to a time-power law, with an anomalous diffusion exponent, (between and

and ). This exponent and

the generalized diffusion coefficient are computed varying the relevant parameters (surface charge, density, salt-concentration). We remark that the subdiffusion is significant only for strong surface charges and densities, and low-salt concentrations. The existence of a cage effect is shown computing the velocity auto-correlation function of the random walker. It is found that, in a cage, this function is governed by an underdamped (oscillatory) behaviour, for strong densities and surface charges, and low-salt concentration. In the inverse situation, however, we observe that this correlation-function is rather overdamped (non-oscillatory). In the two cases, at large-time, this function fails according to a time-power law, with the exponent . To valid our simulation data, we propose a memory diffusion theory that is based essentially on a generalized Langevin equation. Finally, we demonstrate that the results from simulations are in good agreement with the predictions of the elaborated theory.

Keywords: Pickering emulsions, Sogami-Ise potential, Anomalous diffusion, Cage effect, Meansquare-displacement, Velocity, Auto-correlation-function, Subdiffusion exponent, Generalized diffusion coefficient.

OAJ Materials and Devices, Vol 2, #3, p 33 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Polymer nanocomposites from natural clay: Understanding clay-PEG interactions and their effect on spacing between clay-plates S. Ghyati1*, M. Benhamou2, M. El Jai1, I. Akhrif3 1

Ecole Nationale Supérieure d’Arts et Métiers, Moulay Ismail University, B.P. 15290, Al Mansour, Meknès, Morocco. 2 Faculté des Sciences de Meknès, Université Moulay Ismail, B.P. 11201, Meknès, Morocco. 3 Geoscience and Environment Laboratory, Sciences and Techniques Faculty, Sidi Mohamed Ben Abdellah University, Fez, Morocco. * Author for correspondence: [email protected]

Abstract: During the last decade, interest in nanocomposites based on clay has rapidly been increasing at an unprecedented level, both in industry and in academia, due to their great potential for the enhanced physical, chemical and mechanical properties, compared to the conventionally filled composites. Therefore, the knowledge of the interactions between clay-plates and hydrophilic polymers is of basic interest. We assume that the polyethylene glycol (PEG) chains are grafted onto face-to-face clay-plates. Beside the usual van der Waals attractive interaction, the clay-plates experience a repulsive effective interaction, due to the excluded volume force between monomers along the grafted PEG chains. The face-to-face clay-plates then play the role of polymer brushes. The free energy (per unit area) of a clay-plate pair is the sum of these interactions, and from its expression, we determine the minimal inter-sheet distance, after intercalation, which corresponds to a critical percentage of PEG. Finally, our results are in good agreement with some recent experimental work.

Keywords: Nanocomposites, Clay, Polyethylene glycol (PEG), Intercalations.

OAJ Materials and Devices, Vol 2, #3, p 34 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Investigation of DNA denaturation from generalized Morse potential R. El Kinani1*, H. Kaidi2, M. Benhamou1 1

Physics Department, Faculty of Sciences, P.O. Box 11201, Moulay Ismail University, Meknes, Morocco. ²CRMEF, P.O. Box 255, Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: In this communication, we present a non-linear model for DNA denaturation. We assume that the double-strand DNA interact via a realistic generalized Morse potential that reproduces well the features of the real interaction, as well as the used DNA model and that of Peyrard and Bishop. Using the Transfer Matrix Method, based on the resolution of a Schrödinger equation, we first determine exactly their solution, which are found to be bound states. Second, from the exact expression of the ground state, we compute the denaturation temperature and the free energy density, in terms of the potential parameters. Then, we calculate the contact probability, which is the probability to find the double-strand data at a (finite) distance apart. The main conclusion is that, the present analytical study reveals that the generalized Morse potential is a good candidate for the study of DNA denaturation.

Keywords: DNA, Interactions, Generalized Morse potential, Denaturation transition, Free energy.

OAJ Materials and Devices, Vol 2, #3, p 35 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

The critical current density and the vortex pinning in the organic layered superconductor -(BEDT-TTF)2Cu[N(CN)2]Br H. El Ouaddi1*, A. Tirbiyine1, A. Taoufik1, Y. Ait Ahmed1, A. Nafidi2, H. Chaib2, H. El Hamidi1, A. Hafid1 1

Equipe des Matériaux Supraconducteurs, Université Ibn Zohr, Faculté des Sciences, B.P. 8106, Agadir, Morocco. 2 Equipe Physique de la Matière Condensée et Nanomatériaux pour Energies Renouvelables (LPMCNER), Université Ibn Zohr, Faculté des Sciences, B.P. 8106, Agadir, Morocco. * Author for correspondence: [email protected]

Abstract: The -type BEDT-TTF superconducting salts, [where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene, abbreviated as ET], have a layered structure consisting of superconducting and insulating sheets, similar to HTSC. Consequently, these superconductors have similar characteristic superconducting properties including unconventional metallic properties and competition between antiferromagnetism and superconductivity. This similarity suggests the existence of the vortex phase transition in the organic layered superconductors as observed in HTSC. Because the temperature scale is much lower in organic materials, the thermal fluctuation is expected to be small compared to HTSC. We have reported systematic magnetic measurements on hydrogenated compounds (H 8-Br) and deuterated (D8-Br) of κ-(BEDT-TTF)2Cu[N(CN)2]Br in conditions (ZFC). By cooling the sample with fast, medium and slow rates, our results show that the magnetic properties of these compounds strongly depend on the cooling rate, Vc. It was found that the hysteresis loop is strongly dependent on the cooling rate,

, of the sample through the order processing disorder that affects ethylene’s

C2H2 groups and occurs in the vicinity of

.

The superconducting transition temperature,

, is determined using the dc magnetic susceptibility.

We have found that rapid cooling through 80 K has a pronounced effect on the superconducting transition temperature,

.

We report the effect of the cooling sweep in the vicinity of

of the sample through the order-disorder transformation

for -(BEDT-TTF)2Cu[N(CN)2]Br. This transformation induces a certain

degree of disorder in the conducting planes, and changes the physic of the vortex lattice. The properties of vortex pinning will be sensitive to this disorder. This effect depends on the density of the disordered phase and may also depend on the geometrical configuration of the connection between the defects in this phase. Keywords: Organic superconductor, Critical current, Irreversibility line, Vortex pinning, magnetic measurements.

OAJ Materials and Devices, Vol 2, #3, p 36 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effect of sensor/actuator piezoelectric locationon E-FGM beam dynamics K. El Harti*, M. Rahmoune1, M. Bentaleb1, M. Sanbi2 1

Laboratory of Studies of Advanced Materials and Applications FSM-ESTM, Moulay Ismail University, Meknes, Morocco. 2 National School of Applied Sciences, Abdelmalek Essaadi University, Tetouan, Morocco. *Author for correspondence: [email protected]

Abstract: This work presents a dynamic study of a sandwich beam containing a layer of exponential property gradient materials (E-FGM) and two piezoelectric layers, using the EulerBernoulli theory. The equations of motion are obtained by applying the Hamilton principle. Frequencies of vibration are found by solving the eigenvalues problem. The proposed theory for the dynamic behaviour of gradient sandwich piezo-beam, by varying the location of the piezoelectric couple from the fixed to the free edge, is exploited in the formulation of the active control laws using the control optimal LQG with the Kalman filter.

Keywords: Multilayer beam, E-FGM materials, Piezoelectricity, Euler-Bernoulli, LQG ControlKalman.

OAJ Materials and Devices, Vol 2, #3, p 37 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Znte/cdse type-ii core/shell spherical quantum dot under an external electric field A. Chafai1, I. Essaoudi1,3, A. Ainane1,2,3*, F. Dujardin2, R. Ahuja3 1

Laboratoire de Physique des Matériaux et Modélisation des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Physics Department, Faculty of Sciences, B.P. 11201, Meknes, Morocco. 2 Université de Lorraine, LCP-A2MC, Institut de Chimie, Physique et Matériaux, 1 Bd. Arago, 57070 Metz, France. 3 Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden. * Author for correspondence: [email protected]

Abstract: We have investigated in the framework of the envelope function approximation and taking into account the dependence of the electron effective mass on radius the energy of an electron inside a ZnTe/CdSe core/shell spherical quantum dot. In order to make the problem more realistic we describe the conduction band-edge alignment between core and shell materials by a finite height barrier. By applying the Ritz variational principle the effect of the electric field on the electronic states was also examined. Our numerical results shows the opportunity to control the energy states position of the charge carriers inside our core/shell nanostructures by controlling the size (core radius, shell thickness) of the nanostructure and the strength of the external electric field.

Keywords: Core/shell materials, Nanostructures, Quantum dots, Electric field.

OAJ Materials and Devices, Vol 2, #3, p 38 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

3D tracking of brain tumor by digital holography A. Essadike*, E. Ouabida, A. Bouzid Moulay Ismail University, Faculty of Sciences, Department of Physics, B.P. 11201 Zitoune, Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: By using 2D radiographic images of patients [1-3], we present in this work an original method of reconstructing 3D images by digital holography (Fig. 1). The proposed method is based on integrating the series of space-shifted 2D images into a photonic correlator composed of spatial light modulators and optical elements. A reference wave is added to the Fourier transforms of these images. After processing, the holograms recorded on matrix electronic sensors (spatial light modulators) are converted into electrical current and then recorded in colour digital images on a computer. These holograms obtained allowed us to locate the cancerous tumour and to see its threedimensional shape as well as its connections to the blood vessels and to make a 3D tracking of this tumour. The numerical modelling that we develop reinforces the results which the laboratory studies have already shown, namely the growth of the tumour after chemotherapy. Our model provides not only a spatial and temporal preview of the tumour growth but also suggests that the correspondence of migratory activity could give us an idea of how quickly it grows. The reconstruction method developed in this work allowed us to gain a factor of holograms and to locate the tumour in a volume of

on the reconstruction speed of the digital in time of the millisecond.

The following diagram summarizes the different steps of the 3D reconstruction of the tumour.

Fig.1: Schematic representation of the photonic correlator. Keywords: Digital holography, 3D tracking, Brain tumour, Correlator, MSL.

References: [1] T. Shimobaba, Y. Sato, J. Miura, M. Takenouchi, and T. Ito, Real-time digital holographic microscopy using the graphic processing unit, Optics express, 16 (16):11776-11781, (2008). [2] C. Fournier, L. Denis, and T. Fournel, On the single point resolution of on-axis digital holography, JOSA A, 27(8):1856-1862, (2010). [3] S.Y. Suck, S. Collin, N. Bardou, Y.D. Wilde, and G. Tessier, Imaging the three-dimensional scattering pattern of plasmonic nanodisk chains by digital heterodyne holography, Optics Letters, 36(6):849-851, (2011).

OAJ Materials and Devices, Vol 2, #3, p 39 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effect of TiO2 on electrical, structural and crystallization behavior of alkali tungsten phosphate glasses H. Es-soufi1, L. Bih1*, D. Mezzane2, A. Alimoussa2, B. Manoun3, I. Saadoune4, P. Lazor5 1

Equipe Physico-Chimie de la Matière Condensée, PCMC, Faculté des Sciences de Meknes. Morocco. Laboratoire de la Matière Condensée et Nanostructure – LMCN, Faculté des Sciences et Techniques Guéliz-Marrakech, Morocco. 3 Laboratoire des Sciences des Matériaux, des Milieux et de la Modélisation (LS3M), University Hassan I, 26000, Morocco. 4 Laboratoire de Chimie des Matériaux et de l'Environnement, Faculté des Sciences et Techniques GuélizMarrakech, Morocco. 5 Department of Earth Sciences, Uppsala University, SE-752 36, Uppsala, Sweden. * Author for correspondence: [email protected] 2

Abstract: In this work, phosphate glasses within the Li 2O-Li2WO4-TiO2-P2O5 system were prepared using the melt quenching route. The structure of the obtained samples was analyzed using X-Ray Diffraction (XRD), Infrared Spectroscopy (IR), Differential Scanning Calorimetric (DSC) and Impedance Spectroscopy (IS). XRD patterns justified amorphous nature of the prepared samples. The DSC measurements show the glass transition temperature,

, which increased with increasing

of TiO2 content (mol %). IR spectroscopy highlighted the formation of various structural units and bonds such as Ti-O-Ti, Ti-O-P and P-O-P in the network of the glasses. Impedance spectroscopy is used to determine the electrical properties of the glasses in the frequency range 100Hz-1MHz at various temperatures. The temperature (and composition) dependence of the conductivity is studied and the mechanism of the conductivity is deduced.

Keywords: Phosphate glasses, DSC, IR, Electrical properties.

OAJ Materials and Devices, Vol 2, #3, p 40 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Dirac-equation approach for graphene with an arbitrary potential: Exact analytical results Y. Khaled1*, M. Benhamou2 1

ENSAM, Moulay Ismail University, Meknes, Morocco. Physics Department, Faculty of Sciences, Meknes, Morocco. * Author for correspondence: [email protected] 2

Abstract. In this work, we re-examine the problem of the investigation of the electronic band structures of graphene using the Dirac-equation approach, with massless fermions (electrons). It is assumed that the charges experience a periodic external interaction potential of arbitrary form. First, we study all analytical properties of the wave-function that solves such an equation, and exactly solve the latter for normal incident wave-vectors, whatever is the potential form. Second, we exactly determine the Dirac energy spectrum (at Dirac points). Thirdly, we give a general proof of the Bloch’s theorem usually encountered in Solid State Physics. Finally, the discussion is extended to nonzero gap monolayer-graphenes and to a finite number of parallel graphene layers.

Keywords: Graphene, Electronic band structures, Dirac equation, Bloch’s theorem.

OAJ Materials and Devices, Vol 2, #3, p 41 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Simulation and analysis of light absorption in a new four-layer graphene/metamaterial structure for solar cells B. Mokhtari1*, N. Hissi1, M. Musa Shabat2, N. Cherkaoui Eddeqaqi1, S. Bahsine1 1

Department of Physics, Faculty of Sciences, Laboratory (LAMPE), Moulay Ismail University, Meknes, Morocco. 2 Department of Physics, the Islamic University of Gaza, Gaza Strip, Palestine. * Author for correspondence: [email protected]

Abstract: In this work, a new four-layer graphene/metamaterial structure is modelled as solar cell (Fig. 1). The proposed four-layer cell model consists of silicon substrate, a pair graphenemetamaterial (MTM) layer, and a semi infinite glass cover. The effect of the MTM refractive index and thickness, the graphene conductivity and thickness as well as the effect of the incident angle on the transmittance, reflectance and absorptance are derived and computed. Results show that the absorptance can be controlled by changing the MTM parameters in visible and near-infrared radiation, and also by changing the incident angle. The absorptance of the structure achieves a value greater than

for incident electromagnetic wave of transverse magnetic (TE) polarization.

Fig. 1: The considered structure consisting on a pair of graphene/MTM layer bounded by glass cover and silicon substrate.

Keywords: Metamaterials, Graphene, Waveguide, Solar cell, Absorptance.

OAJ Materials and Devices, Vol 2, #3, p 42 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

The effect of the position and the concentration of Li on structural, electronic, optical and electrical properties of ZnO H. Ahmoum, M. Boughrara*, M. Kerouad Laboratory of Materials Physics and Systems Modeling, Associated Unit to CNRST-URAC: 08, Faculty of Sciences, Moulay Ismail University, B.P. 11201, Zitoune, Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: In this paper, we study the effect of Li position on the formation energy, the crystalline structure, the electronic, the optical and the electrical properties of Li doped ZnO with different concentrations (

,

and

), by using first-principles density functional theory

based on the generalized gradient approximation plus Hubbard U approach (GGA+Ud+Up) and Boltzmann transport theory. In this work, we consider two possible configurations of Li-doped ZnO supercells: substitutional Li for Zn defects (LiZn), and interstitial Li defects (Lii). We have found that the position of Li play an important role on the physical properties of Li doped ZnO. We have also found that our results are in good agreement with experimental and other theoretical studies.

Keywords: First principles, Li doped ZnO, Substitutional, Interstitial.

OAJ Materials and Devices, Vol 2, #3, p 43 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Frequency analysis of nonlinear structures with uncertainties parameters M. Lamrhari1*, D. Sarsri2, L. Azrar3, M. Rahmoune1, K. Sbai1 1

Laboratoire d’Etude des Matériaux Avancées et Applications, FS &EST, Moulay Ismail University, Meknès, Morocco. 2 Laboratoire des Technologies Innovantes, ENSA, Abdelmalek Essaadi University, Tanger, Morocco. 3 Department of Applied Mathematics & Info, ENSET, Mohammed V University, Rabat, Morocco. * Author for correspondence: Tel: +212 66272069, [email protected]

Abstract: Nonlinear phenomena in the dynamics of structures are relatively well known and many methods have been developed to take these into account when dimensioning a structure. Nevertheless, most of these methods are deterministic and not allow considering the uncertainties present in such systems. Indeed, due to the manufacturing process, there is dispersion on the values of certain parameters, the latter can be considered as random. Also for a robust dimensioning objective, it seems necessary to integrate these variations to estimate the associated nonlinear random response. One of the classic methods for taking into account uncertainties is the Monte Carlo method (MCS: Monte Carlo Simulations). This method, based on the resolution of simulations for different values of the random parameters, requires numerous realizations and it is expensive in computation time. Consequently, other methods have been developed; an alternative to MCS approaches is represented by the Polynomial Chaos Expansion (PCE) which describes a stochastic process as a series of orthogonal polynomials with appropriate coefficients. The method PCE has been widely applied for linear structures; it has demonstrated its precision and efficiency for analysis the variability of the linear vibrations in frequency domain. Nevertheless, the latter does not seem capable of dealing with non-linear problems presenting multiple solutions. In this study, we propose a formulation of the problem of non-linear dynamics by considering the random geometric or mechanical physical parameters and by developing the solution on the basis of polynomial chaos. This approach coupled Harmonic Balance Method (HBM) with the polynomial chaos method. The method thus developed will be called stochastic HBM. The difficulty associated with the evaluation of nonlinearity in both the frequency domain and the stochastic domain will be resolved. Several numerical simulations illustrate the efficiency and the precision of the proposed method.

Keywords: Nonlinearity, Uncertainties, Polynomial chaos expansion.

OAJ Materials and Devices, Vol 2, #3, p 44 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Photovoltaic effect and conduction mechanism in BiFeO3 thin films S. Yousfi1, B. Carcan1, F. Le Marrec1, H. Bouyanfif1, M. El Marssi1, S. Matzen2* 1

LPMC EA2081, Université de Picardie Jules Verne 33 Rue Saint Leu, 80000 Amiens, France. Institut d’Electronique Fondamentale, Université Paris-Sud, F91405 Orsay cedex, France. * Author for correspondence: [email protected] 2

Abstract: During the last years, multiferroic materials have gained great attention due to their fundamental physics and possible integration in advanced application. BiFeO 3 (BFO) appears actually as one of the most interesting, because it shows multiferroic properties at room temperature. Recently a peculiar photovoltaic effect has also been revealed in BFO with a large open circuit voltage Voc above the band gap. The very large Voc (up to

) was first interpreted as

arising from the domain structure and electric field at the domain walls. More recently an interpretation based on the symmetry was put forward to explain the anomalous high Voc. In both cases planar geometry of the PV effect was used and the ferroelectric polarization is responsible of the electric field separating the electrons from the holes in the thin films. A smaller Voc

was

however measured in parallel plate capacitor and the origin of this low PV response may be obscured by the possible existence of a Schottky barrier, defects, depolarizing field and the complex rhombohedral ferroelectric domain structure. To better understand the observed PV effect, we have grown by pulsed laser deposition BFO thin films with different thickness on buffered LaAlO 3 substrates. A

thick SrRuO3 layer is used as a bottom electrode while Pt and ITO top

electrodes were deposited. Reciprocal space mappings and Raman spectroscopy were used to characterize the domain structure and symmetry. Ferroelectric properties were investigated using a Sawyer-Tower home made system and piezo-force microscopy. Very large spontaneous polarization were measured and

curves were collected at different temperatures to understand the transport

properties (interface or bulk limited and the existence of a Schottky barrier). PV effects under laser illumination of different wavelength (from

to

) and powers were investigated at

different temperatures. Observed switchable Voc and Isc (short circuit current) will be presented showing that the PV effect arises from the ferroelectric field effect. An attempt to fully understand the electric structure of the BFO films has been performed and an impedance spectroscopy investigation of the ferroelectric PV solar cell will be also presented.

Keywords: Photovoltaic effect, Conduction mechanism, BiFeO3 thin films.

OAJ Materials and Devices, Vol 2, #3, p 45 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Temperature and hydrogen effects on Ll0 FePd magnetic storage material A. Boufelfe* Laboratoire de Physique Université 08 mai 1945 Guelma, B.P. 401 Guelma 24000, Algeria. * Author for correspondence: Fax: +213 37 20 02 60, [email protected]

Abstract: Iron-Palladium (FePd) alloys and multilayers have been subjected to an extensive amount of research on their magnetic properties, in the hope of use in high density magnetic recording media and spintronics applications [1]. Besides, FePd appears to be one of the most promising ferromagnetic shape memory alloys attractive for such practical multifunctional applications as rapid magnetic sensors and magneto-thermo-elastic actuators due to the huge magnetic-field-induced strains [2]. In an earlier work I reported on the electronic, magnetic and elastic properties of mono equi-atomic multilayer of L10 tetragonal structure of 2(FePd)nH

hydride [3]. I showed for the first

time how to polarize and depolarize Pd with H content. In this communication, since finite temperature effects are important in real life applications, I will present the dynamics and thermodynamics properties of this hydride. These findings are computed using a combination of density-functional theory total-energy calculations and density-functional perturbation theory lattice dynamics in the generalized gradient approximation. The vibrational free energy and the expansion, the temperature dependence of the entropy, atomic displacements, Debye temperature and the specific heat are calculated using the quasi harmonic approximation. These results are the corner stone foundation for the evaluation of these materials for a practical use as storage material.

Keywords: Magnetic and electronic materials, Ab initio, FePd multilayers, Elasticity, Magnetic storage.

References: [1] S.D. Bader and S.S.P. Parkin, Spintronics, Annu. Rev. Condens. Matter Phys., 1, 71-88 (2010): [2] T. Kakeshita and K. Ullakko, Giant magnetostriction in ferromagnetic shape-memory alloys, Mrs Bulletin, 27(02), 105-109 (2002). [3] A. Boufelfel, Ab initio calculations of L10 FePdH multilayered structure, International Journal of Hydrogen Energy, 41, 4719-4728 (2016).

OAJ Materials and Devices, Vol 2, #3, p 46 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Electrocaloric measurements in lead-free materials B. Asbani1,2,3*, J.-L. Dellis1, Y. Gagou1, A. Lahmar1, M. Amjoud3, M. Trček4, Z. Kutnjak4, D. Mezzane3, M. El Marssi1 1

LPMC, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cédex, France. ² Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssiniere, B.P. 32229, 44322, Nantes Cedex 3, France. 3 LMCN, F.S.T.G. Université Cadi Ayyad, B.P. 549, Marrakech, Morocco. 4 Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia. * Author for correspondence: [email protected]

Abstract: The electrocaloric (ECE) effect was investigated in lead-free doped Ba0.8Ca0.2TiO3 ceramics synthesized by a conventional sintering process. All analyzed ceramics exhibit tetragonal structure. The dielectric spectroscopy and calorimetry revealed that the Curie temperature decreases as a consequence of elements doping and that the ceramics exhibits a first order ferroelectric phase transition. Direct measurements using high resolution calorimetry were compared to the two indirect measurements using the Maxwell relationship. In a first well-known indirect method, P-E hysteresis loops were measured in a wide temperature range and pyroelectric coefficient and thus the electrocaloric responsivity were determined by derivation of P(T,E) data. In second method the electrocaloric responsivity was determined by direct measurements of the pyroelectric coefficient and consequently the electrocaloric responsivity, , was determined by direct measurements of the pyroelectric currents under different applied electric fields [1]. Good agreement was obtained between different methods and large electrocaloric responsivity was found for some critical compositions around the dielectric maximum [2-4].

Keywords: Electrocaloric effect, Lead-free, Pyroelectric coefficient, Ba0.8Ca0.2TiO3 ceramics.

References: [1] B. Asbani, J.-L. Dellis, Y. Gagou, H. Kaddoussi, A. Lahmar, M. Amjoud, D. Mezzane, Z. Kutnjak, and M. El Marssi, Europhysics Letters, 111, 57008 (2015). [2] B. Asbani, J.-L. Dellis, A. Lahmar, M. Courty, M. Amjoud, Y. Gagou, K. Djellab, D. Mezzane, Z. Kutnjak, and M. El Marssi, Applied Physics Letters, 106, 042902 (2015). [3] H. Kaddoussi, A. Lahmar, Y. Gagou, B. Asbani, J.-L. Dellis, G. Cordoyiannis, B. Allouche, H. Khemakhem, Z. Kutnjak, M. El Marssi, Journal of Alloys and Compounds, 667, 198 (2016). [4] B. Asbani, Y Gagou, J.-L. Dellis, A. Lahmar, M. Amjoud, D. Mezzane, and Z. Kutnjak, Solid State Communications, 237–238, 49–54 (2016).

OAJ Materials and Devices, Vol 2, #3, p 47 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Vibrational properties of carbon peapods (C60@SWCNT) with mono, di and hexa-vacancies defects S.A. Ait Abdelkader, F. Fergani, M. Boutahr, AH. Rahmani, M. Bentalb, H. Chadli, B. Fakrach, A. Rahmani* Laboratory for the Study of Advanced Materials and Applications (LEM2A), Moulay Ismail University, FSM -FLSH-EPF, B.P. 11201, Zitoune, 50000 Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: In general, the synthesized carbon peapods are not perfect as they were once thought to be, and can be contained several kinds of defects. Such defect have an effect on their properties. In order to study the influence of mono, di- and hexa-vacancies defects on the vibrational properties of carbon peapods (C60@SWCNTs), by using a force constant model of Rubio et al. we using the spectral moments method for the diagonalization of the dynamical matrix. In our simulated systems the MV, DV and HV points defects are created and randomly distributed, We systematically calculated the Raman spectra of carbon peapods with such defects as function of their concentrations. The D band are appeared, the ID/IG ratio between (D) band and (G) band intensities are calculated, and the signatures modes of MV, DV and HV are identified. The obtained results are coherent with the experimental result.

Keywords: Carbon peapods, Vibrational properties, Hexa-vacancies defects.

OAJ Materials and Devices, Vol 2, #3, p 48 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Impedance spectroscopy analysis of the diffuse phase transition in lead-free (Ba0,85 Ca0,15)(Zr0.1Ti0.9)O3 ceramic elaborated by sol-gel method S.Belkhadira , S.Ben Moumena, B .Asbani b , M. Amjouda, D. Mezzanea , Igor A. Luk’yanchuk b, E. Choukria , L. Hajjia, Y. Gagoub , M. El Marssib a b

LMCN, F.S.T.G. Université Cadi Ayyad, BP 549, Marrakech, Morocco LPMC, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cédex,

Abstract: We investigate the lead free ferroelectric perovskite ceramic, (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT), prepared by sol-gel method. The as-synthesized precursor powder is calcined at 1000°C for 4h in order to obtain single-phase perovskite structure. X-ray diffraction (XRD) analysis at room temperature shows the formation of single-phase compound with a tetragonal structure refined in P4mm space group. The dielectric measurements in a frequency range of [100Hz-1MHz] and in a temperature range [35-400°C] in the ceramic sintered at 1350°C for 2h, reveal a high maximum dielectric constant ~5200 (100Hz ) at 107 °C, which is associated with ferroelectric –paraelectric phase transition.The sol-gel method has displayed a very important advantages comparing to the conventional solid-state method. Special emphasis was done to characterize diffuse phase transition (DPT) that occurs close to ~107°C. We have shown that the real part of the permittivity close to DPT is well described by Santos–Eiras phenomenological model. Impedance spectroscopy analysis over the frequency range of 100 Hz to 1MHz illustrated mainly bulk contribution up to 300 °C while grain and grain-boundary effects were present above 300 °C using the impedance spectroscopy technique.

Keywords: lead free, sol-gel method, relaxation time, phase transition, unusual behavior, Santos– Eiras, incomplete nature.

OAJ Materials and Devices, Vol 2, #3, p 49 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Raman-active modes in defective peapod F. Fergani*, S. Ait Abdelkader, H. Chadli, B. Fakrach, A H. Rahmani, A. Rahmani Laboratory for the Study of Advanced Materials and Applications (LEM2A), Moulay Ismail University, FSM -FLSH-EPF, B.P. 11201, Zitoune, 50000 Meknes, Morocco. * Author for correspondence: fati.fergani @gmail.com

Abstract: The synthesis and characterization of new one-dimensional (1-D) crystal structures with novel properties are common research areas in the worldwide scientific community [1,2]. It is clear that the unique hollow structure of nanotubes provides an ideal opportunity to create new and welldefined 1-D molecular structures [3,4]. Various peapod structures that use nanotube packing of molecules or atoms have been studied in both experiments and theory [5-6]. In contrast to theoretical considerations, the experimental verifications of the SWNTs (single wall carbon nanotube) strength or Young’s modulus demonstrate evidently discrepancies that may reach even up to [7] originated inherently during production. Structural defects in nanotubes have been identified by STM and HRTEM imaging [8]. Possible single or multiple defects in SWNTs provide an explanation for the extant theoretical experimental differences. Carbon nanotube and nanopeapod characterization and identification rely extensively on their vibrational properties. Raman spectroscopy is widely used by theoretician and experimentalists as a fast and non destructive method to identify the type of nanoparticle and to study their vibrational properties and their electronic structures. In order to improve the comparison with the experimental Raman data measured on defective peapod samples, we calculate the nonresonant Raman spectra of defective C60 and C70 peapods. The non-resonant Raman spectra of these nanomaterials were calculated in the framework of spectral moment method, together with a bond polarizability model. The evolution of the Raman spectrum is discussed, and more attention is paid to the study of the vibrational effect of tri and penta-vacancy in carbon nanotube. Intensity ratio of G band and D band (ID/IG) provides a parameter that can be used to identify the nature of defects at specific concentration. Finally, this work provides benchmark theoretical results to understand the experimental Raman spectra of defective C60 and C70 peapods. Keywords: Raman spectra, Raman-active modes, Defective peapods. References: [1] B.W. Smith, M. Monthioux, D.E. Luzzi, Nature, 396 (1998) 323. [2] L.C. Qin, Phys. Chem. Chem. Phys. 9 (2007) 31. [3] S. Iijima, Nature, 354 (1991) 56. [4] Z.D. Liu, M.G. Yao, Y. Yuan, S.L. Chen, R. Liu, S.C. Lu, B. Zou, T. Cui, and B.B. Liu, J. Raman Spectroscopy, 46 (2015) 413. [5] Z.X. Zhang, Z.Y. Pan, Q. Wei, Z.J. Li, L.K. Zang, and Y.Z. Wang, International Journal of Modern Physics B, 17 (2003) 4667. [6] J. Lu, S. Nagase, S. Re, X. W. Zhang, D.P. Yu, J. Zhang, and R. Han, Phys. Rev.B, 71 (2005) 235417. [7] S.L. Mielke, D. Troya, S. Zhang, J.L. Li, S. Xiao, R. Car, R.S. Ruoff, G.C. Schatz, and T. Belytschko, Chem. Phys. Letters, 390 (2004) 413. [8] A. Hashimoto, K. Suenaga, A. Gloter, K. Urita1, and S. Iijima, Nature, 430 (2004) 870; also, K. Suenaga, H. Wakabayashi, M. Koshino, Y. Sato, K. Urita, and S. Ijima, Nature Nanotechnol., 2 (2007) 358. OAJ Materials and Devices, Vol 2, #3, p 51 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Heteroepitaxial thin films nucleation of edge dislocations dipoles A. Soufi1 1

Université Hassan I, Faculté Polydisciplinaires de Khouribga, Laboratoire des Nanosciences et Modélisations, Khouribga, Morocco. * Author for correspondence: [email protected]

Abstract: Here, the edge dislocations dipoles nucleation from free lateral surfaces near the thin film - substrate interfaces obtained by heteroepitaxial deposition is discussed. For the study, we use the superposition of Boussinesq surface forces and the image dislocations method. For theoretical calculations, we used the conjugate gradient method and Mathematica computer code. The stability of dipoles of edge nucleated dislocations dipoles from free lateral surfaces is studied, which makes it possible to relax the instabilities due to the "Misfit" strains between the thin film and the substrate crystal lattices.

Keywords: Heteroepitaxial deposition, Boussinesq forces, Image dislocations, Dislocations dipoles, "Misfit" strain.

OAJ Materials and Devices, Vol 2, #3, p 52 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

X-ray diffraction and Raman spectroscopy studies of composition induced phase transitions in Ba2-xSrxCdWO6 A. El Aamrani1, B. Manoun1*, R. Abkar1, Y. Tamraoui1, F. Mirinioui1, P. Lazor2* 1

Laboratoire des Sciences des Matériaux, des Milieux et de la Modélisation (LS3M), FPK, Khouribga, Université Hassane I, Morocco. 2 Departement of Earth Sciences, Uppsala University, SE-752 36, Uppsala, Sweden. * Author for correspondence: [email protected]

Abstract: The double-perovskite oxides of general formula AA’BB’O 6, in which A and A' are rare earth metal (Ca2+, Sr2+ or Ba2+ …) and B and B’ are transition metal cations, constitute a wide family of materials displaying varied and appealing electronic and magnetic properties. Recently, a few detailed structural studies have shown that double perovskites exhibit diverse properties such as ferroelectricity [1], ferri- and ferromagnetic [2], superconductivity [3] and catalytic properties [4], etc. The renewed interests in these compounds arise because of the room temperature colossal magneto-resistance (CMR) discovery in Sr2FeMoO6. In addition to their technological applications, these perovskites are also of crystallographic interest. On the other hand, the crystallographic phase transitions as a function of composition are common in this type of perovskite; these transitions are due to the tilting of BO 6/B’O6 octahedra. Thus, these structural changes are often intimately related to the physical properties of materials. In previous studies, similar double perovskites such as A2-xA’xBB’O6 (A/B=Ba, Sr; B/B’=Co, Ni, Zn/Te, W) were thoroughly studied by many researchers. Manoun et al. [5] studied Ba2-xSrxMWO6 (M=Ni, Co) compound by X-ray diffraction and Raman spectroscopy, as a result, a phase transition from cubic to tetragonal phase as a function of composition while increasing strontium amount. However, recent structural study of the double perovskites A2MWO6 (A=Ba, Sr, Ca; M=Ni, Co) by Zhou et al. [6,7] demonstrated that progressively increasing the effective size of the A-type cation by chemical substitution of the alkaline earth cation resulted in the sequence of structural phase transitions: P2 1/n→I4/m→Fm-3m. In another study, this phase transition (P21/n→I4/m→Fm-3m) is present in the structure Sr 2ZnWO6 [8]. In this work, we report that the perovskite Ba2-xSrxCdWO6 was prepared in polycrystalline form by thermal treatment, in air. The study with X-ray diffraction and Raman spectroscopy showed the presence of two phase transitions as a function of composition while increasing strontium amount. A first transition from the cubic symmetry to the monoclinic symmetry Fm-3m → I2/m between

and

symmetry I2/m to the monoclinic symmetry P21/n between

, and a second transition from the monoclinic and

.

Keywords: Double perovskite, Phase transition, Raman spectroscopy, Ba2-xSrxCdWO6. References: [1] C. Ederer and N.A. Spaldin, Current Opinion in Solid State and Materials Science, 9, (2005) 128–139. [2] J.B. Goodenough and J.M. Longo, in: Landolt-Börnstein. Numerical Data and Functional Relationships in Science and Technology, New Series, Group III, Vol. 4, 126 Springer, Berlin (1970). [3] R.J. Cava, B. Batlogg, J.J. Krajewski, R. Farrow, L.W. Rupp, A.E. White, K. Short, W.F. Peck, and T. Kometani, Nature, 332, (1988) 814. [4] M. Misono, Catalysis Today, 144, (2009) 285–291. [5] B. Manoun, A. Ezzahi, and P. Lazor, J. Mol. Struct., 1045, (2013) 1–14. [6] Q. Zhou, B.J. Kennedy, C.J. Howard, M.M. Elcombe, and A.J. Studer, Chem. Mater., 17, (2005) 5357. [7] Q. Zhou, B.J. Kennedy, and M.M. Elcombe, J. Solid State Chem., 180, (2007) 541. [8] B. Manoun, J. M. Igartua, P. Lazor, and A. Ezzahi, J. Mol. Struct., 1029, (2012) 81–85.

OAJ Materials and Devices, Vol 2, #3, p 53 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Raman active modes in single-walled BC3 nanotube bundles A. Elbiyaali*, F. Allali, H. Chadli, M. Bentaleb, A. Rahmani Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A) Université MY Ismail, Faculté des Sciences, BP 11201, Zitoune, 50000 Meknès, Morocco. * Author for correspondence: [email protected]

Abstract: The calculation of polarized nonresonant Raman spectra of chiral and achiral bundles of single-walled BC3 nanotubes (BBC3NT’s) is performed in the framework of the force constants model, using the spectral moment’s method. The calculation of the BBC 3NT Raman active modes as a function of the diameter and chirality of tubes allows us to derive the diameter dependence of the wave number of the breathing-like modes, intermediate-like modes and tangential-like modes in a large diameter range. In particular, the diameter dependence of the wave numbers of the radial breathing-like modes resulting from the in-phase and counter-phase coupled motions of the totally symmetric radial breathing mode (the so-called RBM) of the tubes is discussed. Depending on the relative lengths of the tubes, additional modes are evidenced in the RBM region. These modes must be considered in the analysis of the experimental data, and these results are useful to interpret the experimental Raman spectra of BBC3NTs.

Keywords: Carbon nanotube, Doping, Boron, Raman spectra, Spectral moment.

OAJ Materials and Devices, Vol 2, #3, p 54 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Phase behavior of pH-smart system: microemulsion and polyelectrolyte (PAA) S. Elkhaoui1, R.Ahfir1, M. Filali* 1

Laboratoire de Physique Théorique et Appliquée (LPTA), Université Sidi Mohamed Ben Abdellah Faculté des Sciences Dhar El Mahraz, B.P. 1796, Fès, Atlas, Morocco. * Author for correspondence: [email protected]

Abstract: We have charcterized the phase behavior of the pH-smart system consisting of a neutral microemulsion and polyacrylic acid PAA (polyelectrolyte) at low pH (

). The microemulsion is a

thermodynamically stable dispersion in water of oil nanoparticle surrounded by a surfactant film. The polyacrylic acid (PAA) is a water polymer which is neutral at low pH (

). At low

concentration of PAA addition, the solutions are monophasic and transparent. But, upon increasing the PAA concentration, we observe a phase separation. This associative phase separation is due to the bridging of the nanoparticles by the neutral polyelectrolyte chains through H-bond.

Keywords: Microemulsion, Polyelectrolyte (PAA), H-bond.

OAJ Materials and Devices, Vol 2, #3, p 55 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Prediction of wind speed and production management Y. Amellas, A. Echchelh*, A. Djebli 1

Ibn Tofail University, Kenitra, Morocco. Abdelmalek Essaadi University, Tetouan, Morocco. * Author for correspondence: [email protected] 2

Abstract: The great irregularity of the wind energy is a considerably important property, which represents one of the major disadvantages linked radically to the wind. Then a good prescience of the wind, the production of wind energy and its future productivity, is indispensable, and this in various horizons which can extend from a few days to a few minutes. Indeed, when energy production meets the needs of consumers, it is right there that we talk about optimal efficiency bidisciplinary (Energy and Financial). Therefore, this intermittence complicates the prediction of the power produced by wind energy. In order for the estimate of this power to be good, careful monitoring, good control and a good forecasting tool are compulsory. To this end, industry and international wind energy companies are shedding light on improving energy efficiency so that they can increase production and subsequently develop the activity of the wind sector. The prediction of wind speed is a primary phase in the production process, of which there are two types: Long and short. Long-term forecasting continuously seeks to evaluate the feasibility of the project, to present the lifetime of the park (

years of operation) and also to

estimate the average annual production expected over the same period based on long-term data ( or

years), originating from a weather station or via satellite. While Short Term Prediction (PCT)

predicts wind and production at

,

, a few minutes.... Its main objectives are to announce in

advance (J-h) the production of electricity supplied by wind energy, with the objective of preparing investors to price it on a day-horizon, . Moreover, the assured management of the operation of the wind farms and a better organization of the interventions of the sites is due to a preventive maintenance and a high security.

Keywords: Intermittent wind, Long-term and short-term wind prediction, Production management.

OAJ Materials and Devices, Vol 2, #3, p 56 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effect of MoS2 layers deposited under the gold nanoparticles on the localized surface plasmon resonance M. El Barghouti1*, A. Mir1, A. Akjouj2 1

Laboratory for the Study of Advanced Materials and Applications (LEM2A), Physics Department, Faculty of Sciences, Moulay Ismail University, Meknes, Morocco. 2 Institut d’Electronique, de Microélectronique et de Nanotechnologie, UMR CNRS 8520, Université Lille I, Sciences et Technologies, Avenue Poincaré – B.P. 60069, 59652 Villeneuve d’Ascq, France. * Author for correspondence: [email protected]

Abstract: In this work, we propose a new configuration of the localized surface plasmon resonance (LSPR), based on MoS2 hybrid structures for ultrasensitive biosensing applications. The plasmonic resonances are widely used in bimolecular detection and continue to be an active network because of the rich variety of surface configurations and measurement donations. The present work, studies the interaction of gold nanoparticles with a MoS2 film. MoS2 is used as a thin spacer between the gold nanoparticles and the detection of dielectric medium. MoS 2 monolayers have emerged recently as promising nanostructures for various applications in both the optics and electronics. In this work, we will give an overview of the optical properties of 2D nanostructures based on this new class of materials. A stronger behaviour of the resonance positions in the absorption spectrum exhibited a strong coupling between the LSPR on the gold nanoparticles and the MoS2 coating film.

Keywords: Gold nanoparticle, MoS2-films, Localized surface plasmon resonance.

OAJ Materials and Devices, Vol 2, #3, p 57 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Tetragonal tungsten bronze based glass-ceramics for high energy storage density A. Ihyadn*1,2, L. Bih2, D. Mezzane1, M. Amjoud1, A. Alimoussa1, E. Choukri1 1

Laboratoire de Matière Condensée et Nanostructures, FST, Marrakech, Cadi Ayyad, B.P. 549, 40000 Marrakech, Morocco. 2 Equipe Physico-Chimie la Matière Condensée (PCMC), Faculté des Sciences de Meknès, B.P. 11201 Zitoune, Meknès, Morocco. * Author for correspondence: [email protected]

Abstract: Glass-ceramics materials based TTB (tetragonal tungsten bronze) exhibit a wide variety of chemical composition, the change in composition in most materials affect their crystal structure as well as their dielectric properties. The general formula of the most studied TTB are the following A1A2Nb5O15 (A1Ba, Sr, A2=K, Na). The most studied systems in the literature as lead-free glassceramic based on silica and / or borate glass are (BaO-SrO-Nb 2O5-SiO2)-(BaO-Na2O-Nb2O5-SiO2)(BaO-K2O-Nb2O5-SiO2)-(SrO-Na2O-Nb2O5-SiO2).

Indeed,

, is governed by the dielectric permittivity

the

energy

storage

density,

and breakdown strength

.

Previous studies have shown that the control of heat treatment temperature, chemical composition (TTB) and the addition of nucleating agents significantly improve energy storage density [1,2]. In this present work, Barium potassium niobate-based phosphate system glass–ceramics will be prepared via a melt-quenching combined with the controlled crystallization method. And the structural, dielectric and ferroelectric properties will be investigated.

Keywords: Glass-ceramic, TTB, Energy storage density, Breakdown strength, Phosphate.

References: [1] J. Song et al., Effect of the Sr/Ba ratio on the microstructures and dielectric properties of SrO– BaO–Nb2O5–B2O3 glass–ceramics, Materials Letters, 117 (2014) 7–9. [2] Y. Yang et al., Effect of crystallization temperature on the dielectric property and energy density of SrO–BaO–Nb2O6–B2O3 glass–ceramics, Journal of Non-Crystalline Solids, 410 (2015) 96–99.

OAJ Materials and Devices, Vol 2, #3, p 58 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effects of piezoelectric layer on rayleigh waves behavior in piezomagntic substrate M. Ben Amor*, H. Ezzin Laboratory of Physics of Materials, Faculty of Sciences of Sfax, B.P. 1171, 3000 University of Sfax, Tunisia. * Author for correspondence: [email protected]

Abstract: This work investigates the propagation of Rayleigh waves in a transversely isotropic piezo-electriclayer on a piezo-magnetic half-space. The dispersion relations have been numerically derived and computed by considering the coupling piezoelectric and piezomagnetic behaviors. The magneto-electrically open and short conditions are applied to solve the problem. The phase and group velocity of the Rayleigh wave is numerically calculated for the magneto-electrically open and short cases, respectively. The variations of magneto-electromechanical coupling factor for different piezoelectric layers are also obtained and discussed. The changes in phase velocity, group velocity, and magneto-electromechanical coupling factor due to the change of piezoelectric layer could be a potential factor for designing new type of surface wave devices constructed from piezoelectric and piezo-magnetic materials.

Keywords: Multiferroic composites, Rayleigh waves, Piezo-electric/piezo-magnetic material, Magneto-electromechanical coupling factor.

OAJ Materials and Devices, Vol 2, #3, p 59 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Modeling of the effect of ash on the thermal behavior of cement matrix construction materials A. Lachheb1*, R. Saâdani, R. Agounoun, M. Rahmoune, K. Sbai The Laboratory for the Study of Advanced Materials and Applications (LEM2A), Team of Advanced Materials and Energy Systems (MASEN), FS-EST of Meknes, University of Moulay Ismail, Morocco. * Author for correspondence: [email protected]

Abstract: In Morocco, it is currently difficult to obtain good quality insulation products at affordable prices, hence the need to develop and improve the quality of building materials in terms of thermal insulation by using Techniques for simple production and implementation. The aim of this work is to model the transfer of heat in building materials. The material studied is concrete reinforced with residual ash from the combustion of wood in order to study the effect of ash on the thermal characteristics of cement-based materials. Comparing the energy performance of new materials with those of cement alone will allow us to deduce that new materials are less effusive than cement alone and its integration in the building envelope allows a significant saving of energy.

Keywords: Ash, Hemp concrete, Thermal behavior, Heat equation, Finite element method, TRNSYS.

OAJ Materials and Devices, Vol 2, #3, p 60 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Electronic and optical properties of Sr-doped BaTio3: first-principal studies O. Tahiri*, S. Kassou, R. El Mrabet, A. Belaâraj Laboratoire Physique des Matériaux et Modélisation des Systèmes, CNRST-URAC08, Département de Physique, Faculté des Sciences, Université Moulay Ismail, 50000-Meknès, Morocco. * Author for correspondence: [email protected]

Abstract: The perovskite materials present a numerous technological applications in electro optics, waveguides, laser frequency doubling, high capacity computer memory cells, etc. The ABO3-type perovskite received increasing attention in the last decade by both experimental and theoretical communities; a proper description of their electronic properties is still an area of active research. These types of structures are chemically very flexible i.e. many different cations can be substituted by transition metal ions in both A and B sites without drastically changing the overall structure. In this work, we investigated the band structures, total density of states (DOS) and optical constant in mixed crystal BaxSr1-xTiO3 (

,

and

) by using the first-principles calculations based on

density functional theory (DFT) using a semi local generalized gradient approximation (GGA), implemented in Abinit package. The results show that the electronic structure of Sr-doped depends on the doped concentration, the band gap is an indirect one at the

point in the Brillouin zone and

the energy gap increases with composition, . The refractive index and extinction coefficient were also calculated. The obtained results are in good agreement with the previous experimental ones.

Keywords: Electronic structure, Band gap, Total density of states.

OAJ Materials and Devices, Vol 2, #3, p 61 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Numerical estimation of vanadium dioxide optical properties for building isolation applications O. Iken1*, R. Agounoun1, H. Bouyghf1, A. Zoubir1, M. Rahmoune1, K. Sbai1, R. Saâdani1 1

Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A), Université Moulay Ismail, FS - EST of Meknes, Meknès, Morocco. * Author for correspondence: [email protected]

Abstract: Vanadium dioxide (VO2) is a material that has a great potential for building thermal insulation, spatially with his capacity of radiative rectification which is controlled by his transition temperature. Under the temperature of

, VO2 has a semiconductor crystallographic structure;

therefore it becomes transparent to visible and infrared solar radiations. Above

, VO2 has a

metallic crystallographic structure and become more reflective to the same spectra. This semiconductor/metallic transition influences the optical properties of VO 2 which are highly dependent on temperature and wavelength. These properties are refractive index extinction coefficient,

and

, they are necessary in the optical study of VO2 insulation capacities.

Determination of these properties is purely experimental using ellipsometry techniques. In this work we suggest a method for numerical determination of these optical properties. This method uses the Particle Swarm Optimization algorithm and it is based on the theoretical model of Lorentz oscillators at VO2 nanoparticles scale. We calculated

and

, for

temperatures and

compared them with experimental results; this comparison showed good agreement between numerical and experimental results.

Keywords: Vanadium dioxide, Radiative rectification, Building insulation, Optical properties, Optimization algorithms.

OAJ Materials and Devices, Vol 2, #3, p 62 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Pool boiling heat transfer of liquid nitrogen on a brass ribbon with different positions K. Bouazaoui1*, R. Agounoun1, K. Sbai1, A. Zoubir1, I. Kadiri2, M. Rahmoune1, R. Saâdani1 1

Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A), Université Moulay Ismail, Faculté des Sciences, Ecole Supérieure de Technologie Meknès, Morocco. 2 Université Cadi Ayyad, Faculté des Sciences et Techniques de Marrakech, Morocco. * Author for correspondence: [email protected]

Abstract: The nucleate boiling is a phenomenon of heat transfer which occupies an important place in the industrial sector particularly in the areas of electric power generation and refrigeration, because it enable to reach high flux densities with relatively low temperatures differences. To quantify the thermal exchanges in pool boiling, we realized an experimental study of liquid nitrogen in transient state regime. This investigation has been realized on a brass ribbon in a horizontal and vertical positions subjected to different heat flux densities. The initial conditions for the nucleation sites activation are carried out with a heat flux corresponding to

of the critical flux. Moreover,

the influence of different ribbon positions on the boiling triggering time, superheat of triggering and critical flux density has been investigated.

Keywords: Experimental study, Pool boiling, Liquid nitrogen, Superheat on triggering.

OAJ Materials and Devices, Vol 2, #3, p 63 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Experimental study on the thermal performance of two different insulation materials: Polystyrene and Terra Cotta M. Dlimi*, R. Agounoun, A. Zoubir, K. Sbai, M. Rahmoune, R. Saâdani The Laboratory for the Study of Advanced Materials and Applications (LEM2A), Team advanced Materials and Energy Systems (MASEN), FS - EST of Meknes, University of Moulay Ismail, Morocco. * Author for correspondence: [email protected]

Abstract: The aim of this article is to study experimentally the thermal behavior and the energetic efficiency of a homogeneous multilayer wall. The chosen materials are polystyrene such as an organic insulation material and terra cotta such as an ecological insulation material. This work carried out consists of evaluating one by one the thermal performance of each material by applying three different fluxes with the variation of the material thicknesses from

to

, which allow

us to evaluate their impact on the thermal ability of the wall.

Keywords: Insulation materials, Polystyrene, Terra Cotta, Thermal insulation, Thermal resistance.

OAJ Materials and Devices, Vol 2, #3, p 64 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Theoretical study of Raman active modes in fullerenes C60 and C70 inside single-wall boron nitride nanotubes B. Fakrach, M. Boutahir, F. Fergani, A.H. Rahmani, H. Chadli, A. Rahmani* Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A), Université Moulay Ismail, FSM, BP 11201, Zitoune, 50000 Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: Carbon and boron nitride nanostructures are of considerable interest to researchers from many scientific areas due to their unique electronic and mechanical properties. In particular, a single walled boron nitride nanotube (SWBNNT) [1] and a fullerene peapods (C60@SWCNT) [2], have been reported. The spectral moments method (SMM) [3] was shown to be a powerful tool for determining vibrational spectra (infrared absorption, Raman scattering and inelastic neutron-scattering spectra) of harmonic systems. This method can be applied to very large systems, whatever the type of atomic forces, the spatial dimension, and structure of the material. A usual method to calculate the vibrational spectra requires the eigenvalues and the eigenvectors which can be obtained by direct diagonalization of the dynamical matrix of the system. However when the system contains a large number of atoms, the dynamical matrix is very large and its diagonalization fails or requires long computing time. By contrast, the spectral moments method allows us to compute directly the vibrational spectra of very large boron nitride nanotube systems without any diagonalization of the dynamical matrix. In the following, we use the SMM, together with a bond-polarizability model, to calculate the nonresonant Raman spectrum for infinitely long isolated C60 and C70 peapods (C 60@SWBNNT and C70@SWBNNT). The effect of C60-tube and C70-tube interaction on the mode frequencies both of the peas and the pod has been calculated using the Lennard-Jones, potential showing that the lowest frequency mode region is more affected than the higher one. The tube chirality’s and diameter effects on Raman spectra were studied. These predictions are useful to interpret the experimental data. Keywords: Raman spectra, Boron nitride, Peapods, Spectral moments method. References: [1] B. Fakrach, A. Rahmani, H. Chadli, K. Sbai, M. Bentaleb, J.L. Bantignies, and J-.L. Sauvajol, Phys. Rev. B85, 115437 (2012). [2] H. Chadli, A. Rahmani, K. Sbai, P. Hermet, S. Rols, and J.-L. Sauvajol, Phys. Rev. B74, 205412 (2006). [3] A. Rahmani, J.-L. Sauvajol, S. Rols, and C. Benoit, Phys. Rev. B66, 125404 (2002).

OAJ Materials and Devices, Vol 2, #3, p 65 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Ferromagnetism induced by Cr-, V single and double impurities doped BN from Ab-initio and Monte Carlo study Y. Benhouria1*, M. Bahloul4, M. Houmad4, I. Essaoudi1,5, A. Ainane1,2,3,5, H. Ezzahraouy4, R. Ahuja5 1

Laboratoire de Physique des Matériaux et Modélisations des Systèmes, (LP2MS), Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Faculty of Sciences, Physics Department, B.P. 11201, Meknes, Morocco. 2 Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38D-01187 Dresden, Germany. 3 Laboratoire de Physique des Milieux Denses (LPMD) Institut de Chimie, Physique et Matériaux (ICPM), 1 Bd. Arago, 57070, Metz, France. 4 Laboratory of Magnetism and high-energy physics (LMPHE), Faculty of Sciences, University Mohammed-V, Av. Ibn Batouta, B.P. 1014 Rabat, Morocco. 5 Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden. * Author for correspondence: [email protected]

Abstract: Based upon AB initio electronic structure calculation by the Korringa–Kohn–Rostoker method (KKR), combined with the coherent potential approximation (CPA) method in connection with the local density approximation and Monte Carlo simulations, we investigate electronic and magnetic properties of cubic BN compound doped and co-doped with Cr and V atoms. The calculated electronic structure and density of states of doped BN with single and double impurities can induce localized edge states around Fermi level, leads to semiconductor to half-metal transition. Therefore, the stability of ferromagnetic (FM) and DLM configurations has been discussed. The Curie temperature, magnetization and Susceptibility results for different size of Cr and V co-doped (doped) BN can offer a great interest in spintronics applications.

Keywords: Ab initio calculations, Monte Carlo simulations, KKR-CPA, Diluted magnetic semiconductor.

OAJ Materials and Devices, Vol 2, #3, p 66 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Vibrational properties of single-wall BN-nanotubes inside carbon nanotubes using IR spectroscopy H. Boughaleb, A. M. Nassir, M. Boutahir, AH. Rahmani, B. Fakrach, H. Chadli, A. Rahmani* Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A), Université Moulay Ismail, FSM, BP 11201, Zitoune, 50000 Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: The developments in nanotechnology in last decades have provided use of nanoparticles for many applications in various areas such as electronics, pharmaceutical, cosmetics, and biomedical due to their strengthened mechanical, thermal and electrical properties. Nanotubes have been one of the most regarded and studied type of nanoparticles up to now. The structure of boron–nitride nanotubes is very similar to that of carbon nanotubes (CNT), and they exhibit many similar physical and chemical properties [1]. In particular, a single walled boron nitride nanotube (SBNNT) encapsulated inside CNT have been reported [2]. This hybrid system between BN and carbon nanotubes has generated a lot of interest for electronic applications. The calculations of vibrational properties of SBNNT/CNT hybrid nanostructures are performed in the framework the framework of spectral moments method (SMM) [3], together with a bond polarizability model. A Lennard-Jones potential is used to describe the van der Waals inter-tube interactions. We present the calculation results of the infrared active modes in SBNNTs encapsulated inside carbon nanotubes with finite and infinite sizes. The dependence of the breathing-like modes wavenumber in terms of diameter and chirality is discussed. Effects of van der Waals coupling between SBNNT and carbon nanotubes on charge transfer processes are also investigated. Keywords: CNT, BNNT, SMM, IR. References: [1] Y. Chen, J. Zou, SJ. Campbell, and G. Le Caer, Appl Phys Lett., 84, 2430 (2004). [2] Nakanishi, R. Kitaura, J. H. Warner, Y. Yamamoto, S. Arai, Y. Miyatan, and H. Shinohara Scientific Reports, 3, 1385 (2013). [3] A. Rahmani, J.-L. Sauvajol, S. Rols, and C. Benoit, Phys. Rev. B, 66, 125404 (2002).

OAJ Materials and Devices, Vol 2, #3, p 67 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Evaluation of the performance of a grid connected photovoltaic installed on institutional buildings L. Bouhaki*, R. Saâdani, R. Agounoun, K. Sbai, M. Rahmoune Laboratory for the Study of Advanced Materials and Applications (LEM2A), Moulay Ismail University, Faculty of Science, Superior School of Technology, Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: The grid connected PV systems are largely used in the applications of the renewable energy sources, and it is important to have a capacity to evaluate the performance of the systems installed. In this paper, the grid connected photovoltaic (Poly-Si), is presented, and its performance is evaluated under the weather conditions of Meknes city. The mathematical equations developed for the modelling of the performance of generator PV are based on the characteristic voltage of the module. The model of simulation was validated starting from the experimental data of a grid connected PV system of

installed at the superior School of Technology in Meknes under the

project “propre.ma”, financed by IRESEN Group.

Keywords: Production, Photovoltaic solar modules, Grid-connected photovoltaic system.

OAJ Materials and Devices, Vol 2, #3, p 68 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Modeling the effect of alfa fibers on the thermal behavior of a claybased material O. Boutahir*, R. Saâdani, M. Rahmoune, R. Agounoun, A. Zoubir, K. Sbai Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A), Faculté des Sciences, Université Moulay Ismail, B.P. 11201, Avenue Zitoune, Meknes, Morocco. * Author for correspondence: [email protected]

Abstract: In Morocco, as in the rest of North Africa, the indoor climate of the houses leaves something to be desired. In summer, it is too hot and in winter too cold. This is why many homes install heating and air-conditioning equipment, which consumes large amounts of energy, with the high costs that this entails for them. However, it would be possible to achieve a significant improvement in the indoor climate by using thermally insulating materials. Morocco lacks local materials thermally insulating adaptable to Moroccan technique’s construction. The aim of this work is to model the transfer of heat in a new thermally insulating material, which can be produced with local raw materials at low investment costs. The material is clay reinforced with alfa-fibers, an easy to produce material and perfect for thermal insulation of roofs, often the most important part of a building to be insulated, but also for the insulation of other parts of the building.

Keywords: Alfa-fibers, Thermal insulation, Numerical modelling.

OAJ Materials and Devices, Vol 2, #3, p 69 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Effect of rf power and O2/Ar ratio on structural, optical and electrical properties of ZnO thin films grown by reactive radio frequency sputtering A. Afkir1, Y. El Gabbas², A. El Boujlaidi1, N. Rochdi1, A. Kaddouri1 1

Spectroscopy and Atomic Imaging of Materials Team, Faculty of Sciences Semlalia, Cadi Ayyad University, P.O. 2390, Marrakech 40000, Morocco. ² Laboratory of Nanomaterials for Energy and Environment, Faculty of Sciences Semlalia, Cadi Ayyad University, P.O. 2390, Marrakech 40000, Morocco. * Author for correspondence: kaddouri @uca.ma

Abstract: Zinc oxide (ZnO) is one of the most transparent conductive oxides (TCO’s) which has attracted increasing interest for its many potential applications in solid-state devices such as solar cells, optoelectronics, gas sensing, piezoelectricity etc. In this work, ZnO thin films were prepared by reactive radio frequency sputtering on glass substrates. The effect of radio frequency power and O2/Ar ratio on structural, optical and electrical properties have been studied using X-ray diffraction (DRX), Scanning electron microscopy (SEM), UV-Vis- IR and electrical measurements. Results will be presented and discussed.

Keywords: ZnO, Thin films, Reactive rf sputtering, XRD, Transmission.

OAJ Materials and Devices, Vol 2, #3, p 70 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Evidence of a continuous trap distribution in the alpha-alumina D'peaks S. Bachaoui* Abdus Salam International Centre for Theoretical Physics, Trieste, Italy. * Author for correspondence: [email protected]

Abstract: The thermally phenomena is a study tool and characterization of electrical defects in solids. The existence of the thermo-luminescent (TL) during thermal heating of a solid excited previously, is an evidence of the existence of trapping levels. The originality of this study is to provide various extensions to the simple model; they concern the definition of traps levels that can be characterized by a continuous distribution. This model is applied to the peak D' of an alumina single crystal-alpha. The modeling results in equations to determine the concentrations of charge carriers upon which the expression of the TL intensity. An estimate of solutions using a digital calculation process has been considered. This approach requires the evaluation of certain parameters,

: deep trap,

recombination,

: detrapping coefficient

: trapping coefficient

: the height between the trapping levels and,

: coefficient of

: electron concentration trapped in

snares (traps) disconnected heat. The theoretical curves are numerically analyzed using the Gaussian distribution and then we proceed to comparison adjustments from the corresponding models for different numbers of levels. The results clearly show that the incorporation of the continuous distribution of traps gives better quality adjustments; particularly in the case of the model has two trapping levels.

Keywords: Alpha alumina, Thermoluminescence, Continuous trap distribution, Gaussian distribution, Peak dosimetric modeling.

OAJ Materials and Devices, Vol 2, #3, p 71 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Monte Carlo investigation of dielectric properties in ferroelectric double-walled nanotubes under the effect of uniaxial stresses Y. Benhouria1*, I. Essaoudi1,4, A. Ainane1,2,3, R. Ahuja4 1

Laboratoire de Physique des Matériaux et Modélisations des Systèmes, (LP2MS)Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Faculty of Sciences, Physics Department, B.P. 11201, Meknes, Morocco. 2 Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38D-01187 Dresden, Germany. 3 Laboratoire de Physique des Milieux Denses (LPMD), Institut de Chimie, Physique et Matériaux (ICPM), 1 Bd. Arago, 57070, Metz, France. 4 Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden. * Author for correspondence: [email protected]

Abstract: The uniaxial stress dependence of the dynamic critical temperature of the ferroelectric double-walled nanotubes (DWNTs) was studied. The DIFFOUR model was modified to include the uniaxial stress effect. Both the uniaxial stress and the external electric field were applied on the outof-plane direction of the double-walled nanotubes. The polarization was measured with varying the magnitude of the applied stress and the electric field frequency via the dynamics of the polarization reversal in terms of hysteresis. The study was taken by means of the Dynamic Monte Carlo simulations based on Heat-Bath algorithm. From the results, the district dependence of hysteresis behavior on frequency between low frequency and high frequency was prominent. On the other hand, the remanent and the coercivity significantly decreased with increasing applied stresses. Moreover, the areas under the hysteresis loops also decreased indicating smaller magnitude of energy dissipation. The results agree well with related experiments where applicable.

Keywords: Monte Carlo simulation, Ferroelectrics; DIFFOUR, Double-walled nanotubes.

OAJ Materials and Devices, Vol 2, #3, p 72 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Monte Carlo and Density Functional Theory investigation on the magnetic and electronic properties of hexagonal MnB2 H. Ahmoum, M. Boughrara*, M. Kerouad Laboratory of Materials Physics and Systems Modeling, Associated Unit to the CNRST-URAC: 08, Faculty of Sciences, Moulay Ismail University, B.P. 11201, Zitoune, Meknes, Morocco * Author for correspondence: [email protected]

Abstract: By using density functional theory, the electronic structure, density of states, magnetic moment and exchange coupling of hexagonal MnB2 have been investigated. The obtained results from DFT calculations are used as input parameters for Monte Carlo simulations. The magnetic properties of MnB2have been studied by mean of Monte Carlo with heat bath algorithm. The variation of magnetization, susceptibility and capacity calorific with the temperature are also investigated. From our calculations, we found that MnB 2 is good candidate for spintronic applications.

Keywords: Density functional theory, Monte Carlo, Electronic structure, Magnetization, MnB2.

OAJ Materials and Devices, Vol 2, #3, p 73 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Magnetic and electronic properties of V and Mn co-doped GaN from Ab-initio calculations and Monte Carlo simulations study I. Bouziani1*, Y. Benhouria1, M. Bahloul4, I. Essaoudi1,5, A. Ainane1,2,3,5, R. Ahuja5 1

Laboratoire de Physique des Matériaux et Modélisations des Systèmes, (LP2MS) Unité Associée au CNRST-URAC 08, University of Moulay Ismail, Faculty of Sciences, Physics Department, B.P. 11201, Meknes, Morocco. 2 Max-Planck-Institut für Physik Complexer Systeme, Nöthnitzer Str. 38 D-01187 Dresden, Germany. 3 Laboratoire de Physique des Milieux Denses (LPMD) Institut de Chimie, Physique et Matériaux (ICPM), 1 Bd. Arago, 57070, Metz, France. 4 Laboratory of Magnetism and High-Energy Physics (LMPHE), Faculty of Sciences, University Mohammed-V, Av. Ibn Batouta, B.P. 1014 Rabat, Morocco 5 Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden. * Author for correspondence: [email protected]

Abstract: In this work, we have investigated the magnetic and electronic properties of (V,Mn) codoped GaN using the first principles calculations. Based on the Korringa–Kohn–Rostoker (KKR) method combined with the coherent potential approximation (CPA) method, within the generalized gradient approximation (GGA) approximation, we have found that the ferromagnetic state and the half metallicity with

spin-polarization at the Fermi level, can be stabilized when (Ga,V)N is

co-doped with Mn. The total magnetic moment of Ga 1-2xVxMnxN is mainly originated from the V and Mn atoms, and it is observed that the magnetic moment of V increases with the increase of V concentration in Ga1-2xVxMnxN system. The exchange interactions are obtained from the firstprinciples calculations and using Ising-model. Our calculation is supported by Monte Carlo simulations based on the heat bath algorithm. We have examined the effects of magnetic parameters on magnetization, internal energy and magnetic susceptibility.

Keywords: Ab-initio calculations, Monte Carlo simulations, Diluted magnetic semiconductor, GaN.

OAJ Materials and Devices, Vol 2, #3, p 74 (2017) – DOI: 10.23647/ca.md20172012

Second International Symposium on Physics of Data Storage (ISPDS-2) Meknes, Morocco, https://ispds2.sciencesconf.org/

Vibrational properties of boron nitride nanotubes with mono, di and tri-vacancies defects A. Ait Abdelkader, M. Boutahir, AH. Rahmani, B. Fakrach, H. Chadli, M. Bentaleb, A. Rahmani* Laboratoire d’Etude des Matériaux Avancés et Applications (LEM2A), Université Moulay Ismail, FSM-ESTMFPE, B.P. 11201, Zitoune, 50000 Meknes, Morocco. * Author for correspondence: [email protected]

Abstract:The spectral moment’s method [1], can be applied to very large systems, whatever the type of atomic forces, the spatial dimension, and structure of the material, and it’s was shown to be a powerful tool for determining vibrational spectra (infrared absorption, Raman scattering [2] and inelastic neutron-scattering spectra) of the harmonic systems. In this work, in order to obtain the signature of Mono, Di and Tri-vacancies (MV, DV and TrV) points defects, and the effect of such defects on the vibrational properties of boron nitride nanotubes. By using the spectral moment’s method, we systematically calculated the non-resonant Raman spectra of pristine and defective single walled boron nitride-nanotube, with different concentrations of MV, DV and TrV randomly distributed. In comparison with Raman spectra of pristine nanotube, the shift of RBM and TM modes and the apparition of D band are shown, and the characteristics Raman modes of MV, DV and TrV points defect are identified. A comparison with other calculations is performed. Keywords: Raman spectra, Mono-vacancy, Di-vacancy, Boron nitrid nanotube, Spectral moment methods.

References: [1] A. Rahmani, J.-L. Sauvajol, S. Rols, and C. Benoit, Phys. Rev. B 66 (2002), 125404. [2] H.Y. He and B. C. Pan, Phys. Rev. B 77, 073410 (2008).

OAJ Materials and Devices, Vol 2, #3, p 75 (2017) – DOI: 10.23647/ca.md20172012