[22p-A205-1~18] 10.2 スピン基盤技術・萌芽的デバイス技術

△ [22p-A205-7] Enhancement of spin-orbit torque in W/CoFeB/MgO by oxidation of W

〇千葉 峻也^1,2、竹内 祐太朗³、De Zoysa K. Vihanga^1,2、大野 英男^1,3,4,5、深見 俊輔^1,2,3,4,5,6 (1.東北大通研ナノ・スピン実験施設、2.東北大工学研究科、3.東北大AIMR、4.東北大CSIS、5.東北大CIES、6.稲盛科学研究機構 InaRIS)

キーワード：スピントロニクス、スピン軌道トルク、プラズマ酸化

Spin-orbit torque (SOT) can fast switch the magnetization direction, showing promise for the write operation of nonvolatile spintronics devices. SOT is known to arise in nonmagnet/ferromagnet heterostructures under electric current injection and has two components, the Slonczewski-like torque (SLT) and field-like torque (FLT), where the former mainly drives the magnetization switching. While a large SOT has been observed in W-based heterostructures, a previous work showed an enhanced SOT with an increase in the W resistivity by oxygen incorporation through sputtering in oxygen atmosphere. In this work, we study the SOT in W/CoFeB/MgO where the W is oxidized by plasma treatment. The result shows that the SOT significantly increases with increasing the oxidation time whereas the resistivity is almost unchanged.