Structural and relaxor behavior in lead-free (Ba0.8Sr0.2)Ti1-x(Zn1/3Nb2/3)xO3 ceramics

The Solid solutions of (1-x)Ba0.8Sr0.2TiO3-xBa(Zn1/3Nb2/3)O-3 (BST-BZN) with 0.025 <= x <= 0.15 were prepared by a high temperature solid-state reaction technique. The effects of the Ba(Zn1/3Nb2/3)03 addition on the phase composition in the B site on structural and dielectric properties was investigated. The room temperature X-ray diffraction analyses of all ceramics revealed a perovskite phase with a composition dependent symmetry. The temperature and frequency dependence of the dielectric permittivity and losses have been explored. While ceramics of compositions x <= 0.05 showed normal ferroelectric behavior, while ceramics with x >= 0.1 were of relaxor type. It was found that degree of diffuseness and the relaxor effect increased, whereas the transition temperature (T-C or T-m) decreased when both zinc and niobium were introduced in the Ba0.8Sr0.2TiO3 lattice. For the composition with x >= 0.1, the frequency depend on Tm, satisfying the Vogel-Fulcher formula, which indicates a relaxor bahavior. (C) 2016 Published by Elsevier Ltd and Techna Group S.r.l.