Two distinct dielectric relaxation mechanisms in the low-frequency range in Bi₅TiNbWO₁₅ ceramics

Abstract

The ac data in terms of impedance and dielectric loss(tanδ) were exploited simultaneously to probe the dielectric relaxation mechanisms in Bi₅TiNbWO₁₅ceramics. It was found that two distinct relaxation mechanisms exist in the low-frequency range (10Hz–5MHz). One is attributed to the grain boundaryrelaxation and the other is associated with oxygen ion diffusion. Furthermore, the temperature dependence of the oxygen vacancyrelaxation strength is analogous to the Curie-Weiss law and follows the traditional point defectrelaxation theory. These results could be helpful to understand the phenomena related to ferroelectric fatigue, oxygen ion conductivity, etc. Show more