Electrical, magnetic, magnetodielectric, and magnetoabsorption studies in multiferroic GaFeO3

Abstract

We report electrical, magnetic, magnetodielectric, and magnetoabsorption properties of a polycrystalline GaFeO3. The resistivity measurement shows that the sample is highly insulating below 200 K and the resistivity above 200 K obey the Arrhenius law with an activation energy of Ea =0.67 eV. An anomaly occurs in the temperature dependence of permittivity (ε) near the ferrimagnetic transition temperature (TC =228 K) in a zero magnetic field and it is suppressed under μ0H=60 mT which indicates a possible magnetoelectric coupling in GaFeO3 with a fractional change of Δε/ε=-1.8% at 60 mT around TC. The coercivity (HC) of the sample increases dramatically with lowering temperature below 200 K from 0.1 T at 200 K to 0.9 T at 5 K. Magnetoabsorption was studied with a LC resonance technique and we found a close correlation between the shift in the resonance frequency due to applied magnetic field and the coercive field measured using dc magnetization measurements. Our results obtained with multiple techniques suggest that GaFeO3 is an interesting ferrimagnet with potential applications in future multiferroic devices. © 2009 American Institute of Physics.