Giant non-volatile magnetoelectric effects via growth anisotropy in Co 40 Fe 40 B 20 films on PMN-PT substrates

Abstract

Uniaxial magnetic anisotropy was imposed on a CoFeB film by applying an in-plane magnetic field during growth. Electrically driven strain from a ferroelectric 0.68Pb(Mg 1/3 Nb 2/3 )O 3 -0.32PbTiO 3 (011) substrate resulted in giant magnetoelectric effects, whose coupling constant peaked at a record value of ∼8.0 × 10 -6 s m -1 . These large magnetoelectric effects arose due to non-volatile 90° rotations of the magnetic easy axis, reflecting a competition between the fixed growth anisotropy and the voltage-controlled magnetoelastic anisotropy. In contrast to previous work, our non-volatile rotations did not require the assistance of an applied magnetic field or the setting of an in-plane substrate polarization prior to deposition.