Sinterability and nonlinear dielectric properties of Ba 0.6Sr 0.4TiO 3 derived from a citrate method

Abstract

Ba 0.6Sr 0.4TiO 3 powder was prepared by a citrate precursor method, and the sinterability and nonlinear dielectric properties of the resulting specimens were investigated. Superfine powder with a pure perovskite phase was produced at a relatively low calcining temperature of 650 °C by carefully controlling the synthesis process. Adopting the superfine powder was found to be effective in reducing sintering temperature and forming a fine-grained microstructure, which in turn contributed to reducing the dielectric loss and enhancing the figure of merit (FOM). At room temperature, the ceramic specimen sintered at 1250 °C attained a dielectric loss of 0.22% at 10 kHz and a FOM of 142 at 10 kHz and 20 kV/cm. Moreover, a remarkable contribution of polar micro-regions to the nonlinear dielectric behavior was revealed for the ceramic specimen. This phenomenon was qualitatively interpreted with respect to the dielectric responses of the micro-regions under bias electric fields of different magnitudes.