Microstructure and Dielectric Properties of Bismuth Copper Tantalate as Internal Barrier Layer Capacitor Ceramic

摘要

The paper presents synthesis, sintering procedure, microstructure and dielectric prop erties of a new high permittivity perovskite material relative to Cu_2Ta_4O_(12), with the composition Bi_(2/3)CuT_a4O_(12) Impedance spectroscopic studies carried out at frequen cies 10 Hz-2 MHz and in a temperature range -55 to 740° C revealed two dielectric responses. The high-frequency and low-temperature response was attributed to grains, and the low-frequency and high-temperature one - to grain boundaries. The high di electric permittivity was suggested to be related to spontaneous formation of internal barrier layers at the grain boundaries of the semiconducting grains.