Effect of Cr substitution on the structure and electrical properties of BiFeO₃ceramics

Abstract

Polycrystalline BiFe1−xCrxO3 ceramics with x = 0–1 have been produced via a mixed oxide route. The effects of Cr substitution on the structure and on the electrical and ferroelectric properties of BiFe1−xCrxO3 samples have been studied by performing x-ray diffraction, dc resistivity and dielectric measurements as well as characterizing the polarization-field hysteresis loop. The results indicate that the structure of BiFeO3 can be altered dramatically with a small amount of Cr doping (x = 0.005–0.1). Substitution of Cr for Fe results in large variations in the resistivity of BiFeO3 ceramics. The resistivity of BiFe1−xCrxO3 samples reaches a maximum value of 2 × 1012 Ω cm at x = 0.1, which is about two and a half times higher than that for pure BiFeO3. Doping with 1 mol% Cr increases the dielectric constant and the remnant polarization to four and ten times, respectively, as large as those of a pure sample. There is a strong correlation between the electrical resisitivity, the dielectric constants and the remnant polarization of BiFe1−xCrxO3 ceramics.