Tunable magnetization and spin transfer induced by electric field in magnetic ultrathin BiFeO3 layer

First-principles density-functional theory calculations show that switching of magnetization by 90 degrees can be achieved in BiFeO3 ultrathin film by applying external electric field. Spin-up carriers appear to the surface with positive field while spin-down ones to the negative field surface, arising from the redistribution of Fe-t(2g) orbital. The half-metallic behavior of Fe-3d states in the surface of rhombohedral phase film makes it a promising candidate for antiferromagnetic/ferromagnetic bilayer heterostructure possessing electric field tunable ferromagnetic magnetization reversal and opens a new way towards designing spintronic multiferroics. The interface exchange-bias effect in this BiFeO3/ferromagnetic bilayer is mainly driven by the Fe-t(2g) orbital reconstruction, as well as spin transferring and rearrangement. (C) 2013 AIP Publishing LLC.