Temperature dependent conductivity of Bi4Ti3O12 ceramics induced by Sr dopants

Abstract

Abstract Bi4Ti3O12 is an important lead-free ferroelectric material. Doping modification of Bi4Ti3O12 has attracted great attention to improving its performances. In this work, the effect of Sr dopants on the microstructure, dielectric, and conductivity of Bi4Ti3O12 ceramic was investigated by XRD, SEM, and AC impedance spectroscopy. Substitution of 1 at% Sr for Bi decreased the grain size, suppressed the dielectric dispersion of Bi4Ti3O12 ceramic at room temperature, and resulted in different effects on the conductivity of grains and grain boundaries. The conductivity of grains in Bi4Ti3O12 ceramic was increased by the small amount of Sr dopants in the whole experimental temperature range. While the grain boundaries of 1 at% Sr-doped Bi4Ti3O12 exhibited lower conductivity than pure Bi4Ti3O12 below ~380 °C and higher conductivity above ~380 °C. The experimental phenomena were interpreted in term of compensating defects for Sr dopants.