Characterization of spin-orbit torques (SOTs) in the perpendicular magnetic anisotropy (PMA) system is of great importance for fundamental studies and technological applications in spintronic devices. Here, we report a spin Hall magnetoresistance (SMR) based spin-torque ferromagnetic resonance (ST FMR) study of SOT efficiency in perpendicularly magnetized $\mathrm{W}$/${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}$/$\mathrm{Mg}\mathrm{O}$ structures. A full analysis of the ST FMR spectrum is developed for the PMA sample. A typical ST FMR spectrum of the PMA system shows two resonance modes, i.e., in-plane and out-of-plane magnetization precession modes. By performing modulation of the damping measurement for the in-plane mode, the dampinglike torque efficiency is determined to be −0.38, which is consistent with the reference value obtained in samples with in-plane magnetic anisotropy. The dampinglike torque efficiency of −0.31 is also obtained from the out-of-plane resonance mode, in which the significant contribution of the spin-pumping-induced inverse spin Hall effect is carefully considered. The obtained values of dampinglike torque efficiency by different means are consistent with each other. The present work provides useful insights to determine the dampinglike torque efficiency of the PMA sample via ST FMR measurements.

中文翻译：

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通过自旋转矩铁磁共振表征具有垂直磁各向异性的磁异质结构中的自旋轨道转矩效率

垂直磁各向异性（PMA）系统中自旋轨道转矩（SOT）的表征对于自旋电子学设备的基础研究和技术应用非常重要。在这里，我们报告基于自旋霍尔磁阻（SMR）的自旋扭矩铁磁共振（ST FMR）对垂直磁化SOT效率的研究$\mathrm{w\; ^}$/${\mathrm{有限公司}}_{40}{铁}_{40}{\mathrm{乙}}_{20}$/$镁\mathrm{Ø}$结构。对PMA样品进行了ST FMR光谱的全面分析。PMA系统的典型ST FMR频谱显示出两种共振模式，即面内和面外磁化进动模式。通过针对面内模式执行阻尼测量的调制，将类阻尼转矩效率确定为-0.38，这与在具有面内磁各向异性的样本中获得的参考值一致。还可以从平面外共振模式获得−0.31的类似阻尼的转矩效率，其中仔细考虑了自旋泵引起的逆自旋霍尔效应的重要贡献。通过不同方式获得的类似阻尼的转矩效率值彼此一致。