[10p-S302-1~18] 10.2 スピン基盤技術・萌芽的デバイス技術

▼ [10p-S302-11] Spin-orbit torque induced chiral-spin rotation of non-collinear antiferromagnet

〇Yutaro Takeuchi¹、Yuta Yamane^2,3、Ju-Young Yoon^3,4、Ryuichi Itoh^3,4、Butsurin Jinnai¹、Shun Kanai^3,5,6、Jun'ichi Ieda^3,7、Hideo Ohno^1,3,4,5,6,8、Shunsuke Fukami^1,3,4,5,6,8 (1.AIMR, Tohoku Univ.、2.FRIS, Tohoku Univ.、3.Laboratory for Nanoelectronics and Spintronics, RIEC, Tohoku Univ.、4.Graduate School of Engineering, Tohoku Univ.、5.CSRN, Tohoku Univ.、6.CSIS, Tohoku Univ.、7.ASRC, JAEA、8.CIES, Tohoku Univ.)

キーワード：spintronics, antiferromagnet, spin orbit torque

Electrical manipulation of magnetic materials by current-induced spin torque constitutes the basis of spintronics. Here, we show an unconventional response to spin–orbit torque of a non-collinear antiferromagnet Mn₃Sn , which has attracted attention owing to its large anomalous Hall effect despite a vanishingly small net magnetization. In epitaxial heavy-metal/Mn₃Sn heterostructures, we observe a characteristic fluctuation of the Hall resistance under the application of electric current. This observation is explained by a rotation of the chiral-spin structure of Mn₃Sn driven by spin–orbit torque. We find that the variation of the magnitude of anomalous Hall effect fluctuation with sample size correlates with the number of magnetic domains in the Mn₃Sn layer. In addition, the dependence of the critical current on Mn₃Sn layer thickness reveals that spin–orbit torque generated by small current densities, below 20 MA cm⁻² , effectively acts on the chiral-spin structure even in Mn₃Sn layers that are thicker than 20 nm. The results provide additional pathways for electrical manipulation of magnetic materials.