Magnetization switching by spin-orbit torque in Pt with proximity-induced magnetic moment

Abstract

The switching of the magnetization direction induced by the spin-orbit torque in a perpendicularly magnetized Pt/Co/Pd structure has been investigated using X-ray magnetic circular dichroism. An electrical current injected parallel to the layers generates a spin current in a direction that is normal to the current in the Pt layer, and this spin current is generally considered to exert a torque on the adjacent ferromagnetic Co layer. A part of the Pt layer itself, however, is also in a ferromagnetic state, owing to the ferromagnetic proximity effect. Using the anomalous Hall effect, the magnetization reversal of the system is observed by injecting a sufficiently large electrical current into the sample, under a constant external magnetic field that is applied parallel to the injected current. In addition, by conducting element-specific XMCD magnetization measurement, the switching of not the Co but the Pt magnetization is clearly detected.