Intrinsic and extrinsic contributions in non-linearity dielectric response of (Bi0.5Na0.3K0.2)TiO3-(Ba0.8Ca0.2)TiO3 based SrTiO3 ceramics driven by Rayleigh model

Abstract

Pb-free ceramics of [(0.95-x)(Bi0.5Na0.3K0.2)TiO3-0.05(Ba0.8Ca0.2)TiO3 doped x(SrTiO3) (0.0 ≤ x ≤ 0.2) were prepared by solid solution technique. The effect of ST content on the crystal structure and morphology of the sintered ceramics were systemically investigated. Crossover phase transition from ferroelectric to relaxor accompanied by changes in the shape of grain morphology were observed by increasing ST-content. The phase crossover is caused by oxygen vacancies and 1attice distortion effect. The electrical properties for virgin and poled samples were investigated. All virgin samples belong (x ≤ 0.15) showed present ferroelectric to relaxor diffused phase transition however ST = 0.2, only relaxor to paraelectric phase transition was detected in whole range of temperature. The poled sample of ST = 0.2 showed present two phase transition similar to (ST ≤ 0.15) denote domain grow caused by domain wall displacement at high amplitude of electric field. The polarization response was studied under sub-switching cyclic of electric fie1ds at different temperatures. The non-linearity behavior showed both of ferroe1ectric and relaxor phase dominated by Rayleigh-type dynamic. The results suggest that in ferroelectric phase, the extrinsic contribution caused by domain wall motion is responsible for majority of dielectric contributions while in relaxor phase, the majority of dielectric contribution are comes from intrinsic contribution caused by lattice distortion effect. Corresponding author: abdelrazek.mahmoud@sci.svu.edu.eg