Signatures of magnetism control by flow of angular momentum

• 成果类型: Article
• 署名作者: Chen, L.; Sun, Y.; Mankovsky, S.; Meier, T. N. G.; Kronseder, M.; Sun, C.; Orekhov, A.; Ebert, H.; Weiss, D.; Back, C. H.
• 署名单位: Technical University of Munich; University of Munich; University of Munich; University of Regensburg; Technical University of Munich; University of Munich; Technical University of Munich; University of Munich; Technical University of Munich
• 刊物名称: Nature
• ISSN/ISSBN: 0028-5664
• DOI: 10.1038/s41586-024-07914-y
• 发表日期: 2024-09-19
• 页码: 548-553
• 关键词: spin-orbit torques; driven; symmetry

摘要

Exploring new strategies to manipulate the order parameter of magnetic materials by electrical means is of great importance not only for advancing our understanding of fundamental magnetism but also for unlocking potential applications. A well-established concept uses gate voltages to control magnetic properties by modulating the carrier population in a capacitor structure1-5. Here we show that, in Pt/Al/Fe/GaAs(001) multilayers, the application of an in-plane charge current in Pt leads to a shift in the ferromagnetic resonance field depending on the microwave frequency when the Fe film is sufficiently thin. The experimental observation is interpreted as a current-induced modification of the magnetocrystalline anisotropy Delta HA of Fe. We show that (1) Delta HA decreases with increasing Fe film thickness and is connected to the damping-like torque; and (2) Delta HA depends not only on the polarity of charge current but also on the magnetization direction, that is, Delta HA has an opposite sign when the magnetization direction is reversed. The symmetry of the modification is consistent with a current-induced spin6-8 and/or orbit9-13 accumulation, which, respectively, act on the spin and/or orbit component of the magnetization. In this study, as Pt is regarded as a typical spin current source6,14, the spin current can play a dominant part. The control of magnetism by a spin current results from the modified exchange splitting of the majority and minority spin bands, providing functionality that was previously unknown and could be useful in advanced spintronic devices. Signatures of magnetism control by the flow of angular momentum are observed in Pt/Al/Fe/GaAs(001) multilayers by the application of an in-plane charge current in Pt.