Structural and Dielectric Properties of (Bi_1-xBa_x)(Fe_1-xTi_x)O₃Multiferroic Ceramics

Abstract

Phase transitions, dielectric permittivity, and conductivity of (Bi 1-x Ba x)(Fe 1-x Ti x)O 3 (x = 0.05 and 0.1) [BFO-(Ba,Ti)] multiferroic ceramics have been studied as functions of temperature and frequency. In situ synchrotron x-ray diffraction revealed rhombohedral-cubic transitions in the temperature ranges 760-780 • C in BFO-5%(Ba,Ti), and 720-750 • C in BFO-10%(Ba,Ti). A one-dimensional barrier model with intrinsic barriers B every lattice constant a and extrinsic barriers B + is introduced to describe the dielectric response and conductivity. This work revealed that (Ba,Ti) substitutions can enhance the intrinsic barriers and reduce the hopping rate of charge carriers, thereby giving the desired effect of decreasing the conductivity.