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arXiv · 1706.01622

Quantitative characterization of spin-orbit torques in Pt/Co/Pt /Co/Ta/BTO heterostructure on the magnetization azimuthal angle dependence

Christian Engel·Sarjoosing Goolaup·Feilong Luo·Wen Siang Lew
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Abstract

Substantial understanding of spin-orbit interactions in heavy-metal (HM)/ferromagnet (FM) heterostructures is crucial in developing spin-orbit torque (SOT) spintronics devices utilizing spin Hall and Rashba effects. Though the study of SOT effective fields dependence on the out-of-plane magnetization angle has been relatively extensive, the understanding of in-plane magnetization angle dependence remains unknown. Here, we analytically propose a method to compute the SOT effective fields as a function of the in-plane magnetization angle using harmonic Hall technique in perpendicular magnetic anisotropy (PMA) structures. Two different samples with PMA, Pt/Co/Pt/Co/Ta/BaTiO3 (BTO) test sample and Pt/Co/Pt/Co/Ta reference sample are studied using the derived formula. Our measurements reveal that only the dampinglike field of the test sample with BTO capping layer exhibits an in-plane magnetization angle dependence while no angular dependence is found in the reference sample. The presence of the BTO layer in the test sample, which gives rise to a Rashba effect at the interface, is ascribed as the source of the angular dependence of the the dampinglike field.

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Christian Engel, Sarjoosing Goolaup, Feilong Luo, Wen Siang Lew. 2017-06-06. Quantitative characterization of spin-orbit torques in Pt/Co/Pt /Co/Ta/BTO heterostructure on the magnetization azimuthal angle dependence. https://doi.org/10.1103/physrevb.96.054407

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