High power radio frequency oscillation by spin transfer torque in a Co ₂MnSi layer: Experiment and macrospin simulation

We experimentally and numerically investigated rf oscillation induced by spin transfer torque in a current-perpendicular-to-plane giant magnetoresistance (GMR) device with full-Heusler Co₂MnSi (CMS) layers. High output power (P_rf) of 1 nW was experimentally achieved owing to the large GMR effect resulting from the half-metallic feature of the CMS layers. However, the high power rf oscillation was observed only in the narrow dc current (I _dc) region. Macrospin simulation suggested that the high spin polarization of CMS layers led to narrowing the optimum I_dc region for the rf oscillation.