Kouta KONDOU
Spin-orbit torques (SOT) enable efficient electrical control of the magnetic states of ferromagnets and antiferromagnets. However, the conventional SOT via spin Hall effect (SHE) and Edelstein effect has severe limitation that only in-plane spins accumulate near the surface. Such a SOT is not suitable for controlling perpendicular magnetization, which would be more beneficial for realizing low-power-consumption memory devices.
Recently we focus on magnetic spin Hall effect (MSHE) in the topological Weyl antiferromagnet Mn3Sn, in which the spin-polarization direction of current-induced spin accumulation changes its sign upon flipping the chiral antiferromagnetic order, i.e., the cluster magnetic octupole[1]. Notably, the magnetic order can be controlled by a small external magnetic field[2] or a spin-orbit torque[3]. Here, we will introduce our recent experimental results on the observation of a giant field-like torque via out-of-plane MSHE in the topological antiferromagnet Mn3Sn, whose direction and size can be tuned by changing the direction of the order parameter[4]. Our findings provide a new route for efficient manipulation of magnetic states and realization of novel functionalities by utilizing topological Weyl antiferromagnets. This work was partially supported by JST-CREST(No. JPMJCR18T3) and JST-Mirai(JPMJMI20A1) and the Institute for Quantum Matter, an Energy Frontier Research Center funded by DOE, Office of Science, Basic Energy Sciences under Award # DE-SC0019331.”
[2] S. Nakatsuji, N. Kiyohara, and T. Higo, Nature 527, 212 (2015)
[3] H. Tsai, T. Higo et al., Nature 580, 608 (2020)
[4] K. Kondou et al., Nature Communications 12 6491 (2021)