Sifat elektrik bagi bahan-bahan tersebut disiasat dengan spektroskopi impedans. ... pepejal adalah lebih tinggi daripada bahan induk Bi3Zn2Ta3O14.
Sains Malaysiana 38(3)(2009): 387–393
Synthesis and Characterisation of Cubic Bi3Zn2Ta3O14 and its Related Divalent-Doped Pyrochlore Materials (Sintesis dan Pencirian Kubus Bi3Zn2Ta3O14 dan Pengedopan Dwivalen Bahan Piroklor Berkaitan) KHAW CHWIN CHIEH*, TAN KAR BAN, ZULKARNAIN ZAINAL & LEE CHNOONG KHENG
ABSTRACT
Bi3Zn2Ta3O14, ‘P’, was crystallised in a cubic unit cell with lattice parameter of a=10.5437 (9) Å. The material had permittivity, ε’, of around 58 and dielectric loss, tan δ, of 2.3 × 10-3 at 30oC, 1 MHz; temperature coefficient of capacitance (TCC) of -156 ppm/oC in the range of 30oC to 300oC at 1 MHz. Chemical doping was carried out at either A (Bi1.5Zn0.5-xMx) (Zn0.5Ta1.5)O7, or B site (Bi1.5Zn0.5)(Zn0.5-xMxTa1.5)O7 in search of better performance materials. Various divalent cations such as Cd2+, Ca2+, Mg2+, Ni2+, Pb2+, and Cu2+ were used as dopants. Solid solutions formed were: Bi3Zn2-xCdxTa3O14 (0≤x≤0.5), Bi3Zn2-xMgxTa3O14(0≤x≤0.2), Bi3Zn2-xNixTa3O14 (0≤x≤0.4), Bi3Zn2-xPbxTa3O14 (0≤x≤0.3), Bi3Zn2-xCaxTa3O14 (0≤x≤0.3) and Bi3Zn2-xCuxTa3O14 (0≤x≤0.1). Electrical properties of the materials were investigated using impedance spectroscopy. Conductivities of the solid solutions were higher than that of the parent material Bi3Zn2Ta3O14. These doped materials exhibited similar behaviour as Bi3Zn2Ta3O14, showing a high degree of dispersion of permittivity at low frequencies (
