[10a-M101-1~8] 10.1 Emerging materials in spintronics and magnetics (including fabrication and charactrization methodologies)

△ [10a-M101-1] Ferromagnetic layer thickness dependent domain wall chirality and sign of effective Dzyaloshinskii-Moriya field in W/(Co)FeB/MgO systems

〇(DC)Takaaki Dohi¹, Samik DuttaGupta^1,2,3,4, Shunsuke Fukami^1,2,3,4,5,6, Hideo Ohno^1,2,3,4,5,6 (1.RIEC, Tohoku Univ., 2.CSIS, Tohoku Univ., 3.CSRN, Tohoku Univ., 4.CSIS (Core Research Cluster), Tohoku Univ., 5.CIES, Tohoku Univ., 6.WPI-AIMR, Tohoku Univ.)

Keywords:Heavy metal, Domain wall, Dzyaloshinskii-Moriya interaction

Spin-orbit interaction in broken inversion symmetry systems is prospective for future spintronic devices. In-plane current applied to heavy-metal/ferromagnet (FM) heterostructures with spin-orbit coupling generates spin-orbit torques (SOTs) which allow efficient magnetization switching and domain wall (DW) motion. In these phenomena, interfacial Dzyaloshinskii-Moriya interaction (DMI) is known to play key roles, e.g., stabilizing Néel DW and skyrmion. A W/CoFeB/MgO system is one of the promising material systems for device application owing to a large SOT and DMI strength as well as a low-depinning field. However, interfacial DMI in W/CoFeB/MgO has posed a puzzling question concerning DW chirality; both left-handed and right-handed chiral DWs have been observed. Here, we systematically investigate DW chirality and effective DMI field in W/(Co)FeB/MgO system to shed light on the factors relating to the interfacial DMI.