Effect of Zr4+ Content on the Grain Growth, Dielectric Relaxation Behavior, and Ferroelectric Properties of Ba0.4Sr0.6Ti1−x Zr x O3 Nano-Ceramics Prepared by Different Methods Assisted by Fast Microwave Sintering

Abstract

The effect of Zr4+ content on the grain growth, dielectric relaxation, and piezoelectric properties of Ba0.4Sr0.6Ti1−xZrxO3 (BSTZ; x = 0, 0.02, 0.04, 0.06) ceramics prepared by solid-state (SS) and sol–gel modified hydrothermal (SH) methods assisted by fast microwave sintering was investigated in this study. A combination of x-ray diffraction (XRD), scanning electron microscopy (SEM), impedance analysis, and ferroelectric analysis was used. All the ceramics had pure perovskite structures at room temperature, as seen from XRD patterns, indicating that Zr4+ was incorporated into Ba0.4Sr0.6TiO3 lattices to form a solid solution. In the SEM micrographs, SH samples had higher densities and smaller and more homogeneous grain size than SS samples, which was in agreement with density measurements. Nano-ceramics were obtained by this method. When the temperature dependence of dielectric constant and dielectric loss was studied, SH samples had higher permittivity, better thermally activated relaxation, and lower dielectric loss at high temperature. Ferroelectric characteristics can still be detected in Ba0.4Sr0.6Ti1−xZrxO3 ceramics and residual polarization (Pr) decreased with increasing Zr4+ content.