Rietveld refinement structure, electric, dielectric and ferroelectric properties of lead-free Ba0.985Sr0.015Zr0.10Ti0.90O3 ceramics

Abstract

Ba0.985Sr0.015Zr0.10Ti0.90O3 (BSZT) compound is prepared using the standard solid-state reaction technique to explore for energy storage applications. Samples prepared from this compound are sintered at various sintering temperatures (Ts) of 1200, 1250 and 1300 °C, respectively. Influences of Ts on the structural, morphological, dielectric and ferroelectric properties are studied in detail. Rietveld refinement is used on the X-ray diffraction pattern to confirm the crystal structure of the BSZT samples and each sample indicates the tetragonal phase with the P4mm space group. Interestingly, with increasing Ts, the tetragonality increases up to 1250 °C, and then decreases for further increasing Ts, suggesting a transformation to the cubic structure. Morphological analysis of the BSZT samples show that a dense microstructure is attained for higher Ts. Temperature-dependent dielectric studies show that the degree of diffuseness increases up to 1250 °C, and then decreases for further increasing Ts, suggesting a weakening of the relaxor ferroelectric behavior. A non-Debye type relaxation process in the complex impedance and the modulus spectroscopy studies confirm the significant contribution of both the grain and grain boundary to the electrical response of the studied sample. The ferroelectric behaviors of the sample are explored from the polarization versus electric field hysteresis loops. Ferroelectric properties are significantly improved with the Ts.