Bruno mechanism on voltage-controlled magnetic anisotropy in ultrathin cobalt films

摘要

Voltage-controlled magnetic anisotropy (VCMA) in 3J-transition metals such as Fe and Co has been intensively studied [1]. While one mechanism to explain the VCMA is Bruno mechanism [2], that is, voltage-induced change in orbital magnetic moment in ferromagnetic metals, it has recently been pointed out the significance of the electric quadrupole mechanism to the VCMA in case Pt/MgO interface is employed [3]. However, there has been no report experimentally demonstrating the relative significance between the Bruno and the electric quadrupole mechanisms in 3 J-ferromagnetic metals because of alack of direct observation of the voltage -induced change of orbital magnetic moment in ferromagnetic metals.