An effect of electric field on a cone angle at an easy-cone state in CoFeB/MgO stack investigated by ferromagnetic resonance

摘要

Magnetization reversal by spin-transfer torque (STT) is of importance for non-volatile memory applications using magnetic tunnel junctions. Recently, the free layer with an easy-cone state, which can be obtained when the first- and second-order magnetic anisotropy energy constants satisfy a certain condition, is attracting much attention for improving the STT-induced reversal efficiency [1-2]. In this study, we investigate an effect of the electric field E on the cone angle at the easy-cone state in Ta/ CoFeB/ MgO system using ferromagnetic resonance (FMR) to elucidate the variation in the intrinsic critical current under application of voltage.