Temperature dependent conductivity of Bi4Ti3O12 ceramics induced by Sr dopants

Abstract Bi 4 Ti 3 O 12 is an important lead-free ferroelectric material. Doping modification of Bi 4 Ti 3 O 12 has attracted great attention to improving its performances. In this work, the effect of Sr dopants on the microstructure, dielectric, and conductivity of Bi 4 Ti 3 O 12 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 Bi 4 Ti 3 O 12 ceramic at room temperature, and resulted in different effects on the conductivity of grains and grain boundaries. The conductivity of grains in Bi 4 Ti 3 O 12 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 Bi 4 Ti 3 O 12 exhibited lower conductivity than pure Bi 4 Ti 3 O 12 below ~380 °C and higher conductivity above ~380 °C. The experimental phenomena were interpreted in term of compensating defects for Sr dopants.