Sinterability and nonlinear dielectric properties of Ba_(0.6)Sr_(0.4)TiO_3 derived from a citrate method

摘要

Ba_(0.6)Sr_(0.4)TiO_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 per-ovskite phase was produced at a relatively low calcining temperature of 650 deg 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 deg C attained a dielectric loss of 0.22 percent at 10 kHz and a FOM of 142 at 10 kHz and 20kV/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.