Effect of Sm, Co codoping on the dielectric and magnetoelectric properties of BiFeO3 polycrystalline ceramics

Abstract

Multiferroic Bi0.95Sm0.05Fe1−xCoxO3 (x=0−0.1) ceramics were prepared by the rapid liquid phase sintering method. For all the samples studied, the dielectric constant and dielectric loss decrease with increasing frequency in the range from 1kHz to 1MHz. It shows that the dielectric constant of Bi0.95Sm0.05FeO3 at 10kHz is about forty times larger than that of pure BiFeO3. This dramatic change in the dielectric properties of Bi0.95Sm0.05Fe1−xCoxO3 (x=0−0.1) samples can be understood in terms of the space charge limited conduction associated with crystal defects, which was indicated by the increase of magnetoelectric effect with doping Co3+ under applied magnetic field from 1 to 8kOe. It was believed that the ferroelectric polarization enhancement comes from the exchange interaction between the Sm3+ and Fe3+ or Co3+ ions for Bi0.95Sm0.05Fe0.95Co0.05O3 at room temperature.