Relaxor Properties of Doped BaTiO3 Ferroelectrics

Abstract

Perovskite type Ba1-xSrxZr0.2Ti0.8O3 (with x = 0.0, 0.1, 0.2 and 0.3) and Ba1xSrxZr0.3Ti0.7O3 (with x = 0.0, 0.1, 0.2, 0.24, 0.27 and 0.3) ceramics have been synthesized through conventional two step solid state reaction method. The Structural Characterization were investigated using room temperature X-ray diffraction study. All the compositions reveal a single phase cubic structure. The dielectric measurements were taken at various temperature (100 K to 300 K), and at various frequencies (1 kHz to 500 kHz) for all the prepared compositions. This study reveals that the Ba1-xSrxTi0.8Zr0.2O3 (with x = 0.0, 0.1, 0.2 and 0.3) composition does not transform from normal ferroelectric to relaxor ferroelectric while Ba1-xSrxTi0.7Zr0.3O3 (with x = 0.0, 0.1, 0.2, 0.24, 0.27 and 0.3) compositions are of relaxor type and undergo a diffuse type ferroelectric phase transition. The diffusivity increases with increase in Sr concentration in the present composition range. It is observed that with increase in Sr concentration the transition temperature decreases for all the studied compositions. This may occur due to the introduction of smaller ionic radius of Sr+2 at the site of larger ionic radius of Ba+2. It is also observed that with increase in Sr content the maxima of dielectric constant increases for all studied compositions of Ba1xSrxTi0.8Zr0.2O3 (with x = 0.0, 0.1, 0.2 and 0.3). However, for Ba1-xSrxTi0.7Zr0.3O3 the dielectric constant maxima increases up to x = 0.24 and then further increment in Sr content up to x= 0.3, the maxima of dielectric constant shows decrease