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arXiv · 2412.18220

Spin-Splitting Magnetoresistance in Altermagnetic RuO2 Thin Films

Hongyu Chen·Zian Wang·Peixin Qin·Ziang Meng·Xiaorong Zhou·Xiaoning Wang·Li Liu·Guojian Zhao·Zhiyuan Duan·Tianli Zhang·Jinghua Liu·Dingfu Shao·Chengbao Jiang·Zhiqi Liu
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Abstract

The recently discovered altermagnets, featured by the exotic correlation of magnetic exchange interaction and alternating crystal environments, have offered exciting cutting-edge opportunities for spintronics. Nevertheless, the altermagnetism of RuO2, one of the earliest-discovered altermagnets, is currently under intense debate. Here we try to resolve this controversy by demonstrating an altermagnetic spin-splitting magnetoresistance (SSMR) effect that is driven by a spin current associated with the giant nonrelativistic spin splitting of an altermagnet. Compared to the spin Hall magnetoresistance induced by a conventional relativistic spin current, the SSMR is characterized by unusual angular dependence with a phase-shift feature underpinned by the Neel-vector orientation and pronounced temperature dependence caused by its susceptibility to electron scattering. Through systematical investigations on the magnetoresistance of (101)-RuO2/Co bilayers, we disentangle a sizable SSMR and hence unveil a Neel vector along [001] direction. Our work not only demonstrates a simple electric avenue to probing the Neel vector of altermagnets, but also indicates long-range magnetic order in thin films of RuO2.

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Hongyu Chen, Zian Wang, Peixin Qin, Ziang Meng, Xiaorong Zhou, Xiaoning Wang, Li Liu, Guojian Zhao, Zhiyuan Duan, Tianli Zhang, Jinghua Liu, Dingfu Shao, Chengbao Jiang, Zhiqi Liu. 2024-12-24. Spin-Splitting Magnetoresistance in Altermagnetic RuO2 Thin Films. https://doi.org/10.1002/adma.202507764

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