Spin-Splitting Magnetoresistance in Altermagnetic RuO2 Thin Films

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.

40 pages, 13 figures. In press at Advanced Materials

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Cited by in corpus (10)

• Superconducting phenomena in systems with unconventional magnets
• Absence of transport altermagnetic spin-splitting effect in RuO2
• A Theory of Anisotropic Magnetoresistance in Altermagnets and Its Applications
• Exploration of Altermagnetism in $\mathrm{Ru}{\mathrm{O}}_2$
• Observation of mirror-odd and mirror-even spin texture in ultrathin epitaxially strained RuO2 films
• Electric-Field-Controlled Altermagnetic Transition for Neuromorphic Computing
• Magnetic-Field and Strain Engineering of Modulated Transverse Transport in Altermagnetic Topological Materials
• Giant Room-Temperature Third-Order Electrical Transport in a Thin-Film Altermagnet Candidate
• Saturated and Anisotropic Magnetostriction in an Altermagnet
• Spin-Polarized Magnetic Metal Electrodes for Magnetic Tunnel Junctions