Structural and Electrical Properties of Rare Earth Double Perovskite Oxides Ba_(2)CeMO_(6) (M velence Ta~(5+) and Nb~(5+))

摘要

We have synthesized rare earth double perovskite oxides barium cerium niobate Ba_(2)CeNbO_(6) (BCN) and barium cerium tantalate Ba_(2)CeTaO_(6) (BCT) by solid state reaction technique and studied the structural and electrical properties. The x-ray diffraction pattern at room temperature (25 deg C) shows monoclinic structure with the lattice parameters, a velence 5.9763 A, b velence 5.975 A and c velence 8.48 A and beta velence 90.04 deg for BCN and a velence 5.9763 A, b velence 5.975 A and c velence 8.48 A and beta velence 90.034 deg for BCT. Scanning electron micrograph (SEM) shows the formation of grains with different shape and size The AC electrical conductivity (sigma) (velence (omega)(epsilon)_(0)epsilon") is obtained from the temperature dependence of the real (epsilon') and imaginary (epsilon") components of the complex dielectric constant (epsilon)~(*)((velence)(epsilon)'-j(epsilon)"). The frequency dependent conductivity spectra follow the universal power law.