Production of Sr-deficient bismuth tantalates from microwave–hydrothermal derived precursors : structural and dielectric properties

Abstract

Strontium bismuth tantalates were produced for the first time from microwave–hydrothermal precursors at 200 _C, for 2 h. Structural and dielectric properties were investigated by X-ray diffraction and complex impedance spectroscopy. A high ferroelectric–paraelectric transition temperature of 375 _C ðTcÞ was observed, together with two different dielectric regimes for the ac electrical conductivity below Tc. The activation energies were calculated as 0.155 and 0.531 eV, and are related to conduction by oxygen vacancies. It was concluded that the low activation energies showed by these materials could contribute to their fatigue-free nature.