Ferroelectric control of magnetism in BaTiO$_{3}$/Fe heterostructures*

Multiferroics can offer the possibility to manipulate the cross coupled order parameters by conjugate electric and magnetic fields. Switching off ferromagnetic order by an electric field for instance promises significant impact in the design of novel spintronic devices. Here we report on the reversible control of magnetism for a Fe thin film in proximity of a BaTiO$_{3}$ single-crystal. Large magnetization changes emerge in response to ferroelectric switching and structural transitions of BaTiO$_{3}$ controlled by applied electric fields and temperature, respectively.$^{\dag }$ Interface strain coupling is the primary mechanism altering the induced magnetic anisotropy. As a result, coercivity changes up to 120{\%} occur between the various structural states of BaTiO$_{3}$. Up to 20{\%} coercivity change is achieved via electrical control at room temperature. Our all solid state ferroelectric-ferromagnetic heterostructures open viable possibilities for new technological applications. $^{\dag }$S. Sahoo, S. Polisetty, C.-G. Duan, S. S. Jaswal, E. Y. Tsymbal, and Ch. Binek, Phys. Rev. B \textbf{76}, 092108 (2007).