High-temperature dielectric relaxations in (Ce, Y) codoped BaZrO3 ceramics

Abstract

(Ce, Y) codoped BaZrO3 ceramics, BaZr0.1Ce0.7Y0.2O3-δ and BaZr0.4Ce0.4Y0.2O3-δ ceramics were synthesized via solution combustion based on the glycine nitrate process. The dielectric properties of the samples have been investigated in the temperature range from 300 to 1000 K and frequency range from 102 Hz to 106 Hz. It is observed that the samples exhibit colossal dielectric behavior in the temperature below ∼600 K. The colossal dielectric behavior is composed of two sets of relaxations with the low- and high-temperature relaxations being caused by the dipole pairs of -Y and -Y, respectively. In the temperature higher than ∼600 K, the samples show two dielectric anomalies with extremely large dielectric permittivity over 106. It is argued that the low-temperature dielectric anomaly is the typical pseudo-relaxor behavior caused by ion-hopping-motion. While the high-temperature dielectric anomaly results from the negative capacitance effect.