Highly accurate evaluation of spin-torque efficiency by measuring in-plane angular dependence of spin-torque ferromagnetic resonance

スピントルク強磁性共鳴により測定された高精度のスピントルク効率

洞口 泰輔*; 松尾 衛; 能崎 幸雄*

Horaguchi, Taisuke*; Matsuo, Mamoru; Nozaki, Yukio*

Spin-torque ferromagnetic resonance (ST-FMR) is a powerful tool to evaluate spin-torque efficiency (), the efficiency of current-induced torque in metallic bilayers consisting of ferromagnetic and nonmagnetic materials. In general, can be evaluated from the amplitude ratio between symmetric and anti-symmetric components of the ST-FMR spectrum. However, the ratio is also affected by an unnecessary magnetic field owing to the asymmetric alternating current flow used to excite the ST-FMR. In this article, we demonstrate that can be precisely evaluated from the full-angular dependence of the ST-FMR spectrum even though the distribution of alternating current flow is highly asymmetric.