Abstract The spin-orbit torque (SOT) damping-like (field-like) effective fields and efficiencies, HDL(FL) and ξDL(FL), for the MgO substrate/Fe4N (3 nm)/W (5 nm)/cap metallic heterostructure were determined using harmonic Hall and spin-Hall magnetoresistance (SMR) measurements at various temperatures (T). The resistivity of the W layer was measured to be 40 μΩ cm, suggesting a mixed phase of α and β. The sizable anomalous Nernst component was extracted, and a strong T dependence was found. The resultant ξDL(FL) was estimated to be 0.035 (0.015) at T = 300 K, and 0.045 (0.005) at T = 4 K. The longitudinal MR measurements revealed the negative spin polarization of the conduction electrons in the Fe4N layer. However, no sign reversal of the SOT was observed, as in the case where a CoFeB layer with positive spin polarization was employed. The T dependence of ξDL estimated from SMR measurements was in good agreement with that obtained through harmonic Hall measurements, which was indicative of the sizable spin current injection at the Fe4N/W interfaces due to the spin-Hall effect.

中文翻译：

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具有负自旋极化的反钙钛矿 Fe4N 伪单晶薄膜中的自旋轨道扭矩

摘要 MgO 衬底/Fe4N (3 nm)/W (5 nm)/cap 的自旋轨道扭矩 (SOT) 阻尼类（类场）有效场和效率，HDL(FL) 和 ξDL(FL)在不同温度 (T) 下使用谐波霍尔和自旋霍尔磁阻 (SMR) 测量确定金属异质结构。测得 W 层的电阻率为 40 μΩ cm，表明为 α 和 β 的混合相。提取了相当大的异常 Nernst 分量，并发现了很强的 T 依赖性。所得的 ξDL(FL) 在 T = 300 K 时估计为 0.035 (0.015)，在 T = 4 K 时为 0.045 (0.005)。纵向 MR 测量揭示了 Fe4N 层中传导电子的负自旋极化。然而，没有观察到 SOT 的符号反转，就像在使用具有正自旋极化的 CoFeB 层的情况下一样。