講演情報
[22a-P01-19]Gigantic self-induced spin-orbit torque and its strong anisotropy in Weyl ferromagnet Co2MnGa
〇Motomi Aoki1,2, Yuefeng Yin3,4, Simon Granville5,6, Yao Zhang5,6, Nikhil Medhekar3,4, Livio Leiva1, Ryo Ohshima1,2, Yuichiro Ando1,2,7, Masashi Shiraishi1,2 (1.Kyoto Univ., 2.CSRN Kyoto Univ., 3.Monash Univ., 4.FLEET, 5.Victoria Univ. of Wellington, 6.MacDiarmid Institute, 7.PRESTO, JST)
キーワード：
Spin orbit torque、Weyl ferromagnet
Spin-orbit torque (SOT) has been collecting tremendous attention for application to the device utilizing current-induced magnetization control and for fundamental research on charge-to-spin (c-s) conversion phenomenon. Whereas large c-s conversion and resulting SOT has been realized in a variety of systems, anisotropy in the SOT, which enables modulation of SOT efficiency by changing applied-current direction, has been limited to low-symmetry materials.
In this work, we investigate the SI-SOT in Co2MnGa (CMG), a Weyl ferromagnet with L21 crystal structure. As a result, SOT efficiency was comparable to that of heavy metal/ferromagnet bilayers even without any adjacent metal layer. Moreover, sign of the SOT efficiency was reversed with respect to applied-current direction, indicating strong anisotropy in the SOT despite high symmetry in crystal structure. Thickness and capping material dependences of the SOT efficiency, as well as structural analysis and first principles calculations, revealed that large and anisotropic SOT in our CMG films originates from the interplay between topology in band structure and external strain.
In this work, we investigate the SI-SOT in Co2MnGa (CMG), a Weyl ferromagnet with L21 crystal structure. As a result, SOT efficiency was comparable to that of heavy metal/ferromagnet bilayers even without any adjacent metal layer. Moreover, sign of the SOT efficiency was reversed with respect to applied-current direction, indicating strong anisotropy in the SOT despite high symmetry in crystal structure. Thickness and capping material dependences of the SOT efficiency, as well as structural analysis and first principles calculations, revealed that large and anisotropic SOT in our CMG films originates from the interplay between topology in band structure and external strain.