Shuchen Li, Jonathan Gibbons, Stasiu Chyczewski, Zetai Liu, Hsu-Chih Ni, Jiangchao Qian, Jian-Min Zuo, Jun-Fei Zheng, Wenjuan Zhu, Axel Hoffmann
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引用次数: 0
Abstract
Materials with strong spin-orbit coupling and low crystalline symmetry are promising for generating large unconventional spin-orbit torques (SOTs), such as in-plane fieldlike (FL) torques and out-of-plane dampinglike (DL) torques, which can effectively manipulate and deterministically switch an out-of-plane magnetization without the need for additional external in-plane magnetic fields. Here, we report SOTs generated by magnetron-sputtered /Permalloy (Py; )/MgO heterostructures using both spin-torque ferromagnetic resonance (ST-FMR) and second harmonic Hall measurements. We observed unconventional FL and DL torques in our samples due to spins polarized normal to the interface of and Py layers, and studied the influence of crystallographic order and layer thickness on the SOTs. By comparing the Raman spectra of samples prepared in different ways, we found a tensile strain in sputtered films, which might further enhance the generation of unconventional torques by reducing the symmetry of .
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