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arXiv · 1809.11020

Isotropic non-local Gilbert damping driven by spin currents in epitaxial Pd/Fe/MgO(001) films

Yan Li·Yang Li·Qian Liu·Zhe Yuan·Wei He·Hao-Liang Liu·Ke Xia·Wei Yu·Xiang-Qun Zhang·Zhao-Hua Cheng
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Abstract

Although both theoretical predications and experimental observations demonstrated that the damping factor is anisotropic at ferromagnet/semiconductor interface with robust interfacial spin-orbit coupling, it is not well understood whether non-local Gilbert damping driven by spin currents in heavy metal/ferromagnetic metal (HM/FM) bilayers is anisotropic or not. Here, we investigated the in-plane angular- and frequency- dependence of magnetic relaxation of epitaxial Fe/MgO(001) films with different capping layers of Pd and Cu. After disentangling the parasitic contributions, such as two-magnon scattering (TMS), mosaicity, and field-dragging effect, we unambiguously observed that both local and non-local Gilbert damping are isotropic in Fe(001) plane, suggesting that the pure spin currents absorption is independent of Fe magnetization orientation in the epitaxial Pd/Fe heterostructure. First principles calculation reveals that the effective spin mixing conductance of Pd/Fe interface is nearly invariant for different magnetization directions in good agreement with the experimental observations. These results offer a valuable insight into the transmission and absorption of pure spin currents, and facilitate us to utilize next-generation spintronic devices.

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Yan Li, Yang Li, Qian Liu, Zhe Yuan, Wei He, Hao-Liang Liu, Ke Xia, Wei Yu, Xiang-Qun Zhang, Zhao-Hua Cheng. 2018-09-28. Isotropic non-local Gilbert damping driven by spin currents in epitaxial Pd/Fe/MgO(001) films. https://arxiv.org/abs/1809.11020

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