Exchange bias in bilayers based on the ferroelectric antiferromagnet BiFeO3

This paper reports studies of the exchange interaction between the conventional ferromagnets CoFe2O4 and permalloy and the multiferroic antiferromagnet BiFeO3 films. Bilayer films were grown which demonstrated significant exchange bias at room temperature. BiFeO3 films grown under the same conditions also showed a large electric polarization. The results are encouraging for room-temperature applications of BiFeO3 with the combined properties of antiferromagnetism and ferroelectricity, but the significant residual leakage in our BiFeO3 films prevented the demonstration of a stable, controllable exchange bias.