[22p-A205-1~18] 10.2 Fundamental and exploratory device technologies for spin

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

〇Shunya Chiba^1,2, Yutaro Takeuchi³, Vihanga De Zoysa K.^1,2, Hideo Ohno^1,3,4,5, Shunsuke Fukami^1,2,3,4,5,6 (1.Laboratory for Nanoelectronics and Spintronics, RIEC, Tohoku Univ., 2.Graduate School of Engineering, Tohoku Univ., 3.WPI-AIMR, Tohoku Univ., 4.CSIS, Tohoku Univ., 5.CIES, Tohoku Univ., 6.Inamori Research Institute for Science, InaRIS)

Keywords:spintronics, spin-orbit torque, plasma oxidation

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.