[10a-M101-1~8] 10.1 新物質・新機能創成（作製・評価技術）

△ [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)土肥 昂尭¹、DuttaGupta Samik^1,2,3,4、深見 俊輔^1,2,3,4,5,6、大野 英男^1,2,3,4,5,6 (1.東北大, 電気通信研究所、2.東北大, 省エネルギー・スピントロニクス集積化システムセンター、3.東北大, スピントロニクス学術連携研究教育センター、4.東北大, 先端スピントロニクス研究開発センター、5.東北大, 国際集積エレクトロニクス研究開発センター、6.東北大, 原子分子材料科学高等研究機構)

キーワード：重金属、磁壁、ジャロシンスキー・守谷相互作用

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.