[24p-E202-9~17] 10.3 スピンデバイス・磁気メモリ・ストレージ技術

△ [24p-E202-12] フェリ磁性GdFeCo薄膜における電流駆動磁壁移動

〇石橋 未央¹、薬師寺 啓²、河口 真志¹、塚本 新³、中辻 知¹、林 将光¹ (1.東大理、2.産総研、3.日大)

キーワード：磁壁移動、フェリ磁性体

Transition metal (TM) and rare earth (RE) alloy ferrimagnets are unique magnetic systems as the magnetization and angular momentum of the two sublattices can be varied by changing the chemical composition. Antiferromagnetic spin dynamics in TM-RE ferrimagnets near the angular momentum compensation point is attracting great interest owing to the ultrafast dynamics. GdFeCo alloy thin films, a typical RE-TM ferrimagnet, have been widely studied. Recent studies demonstrated field-induced and current-induced domain wall motion over 1 km/s in such system. In this study, we systematically investigated the current-induced domain wall motion for Pt/GdFeCo films with various Gd composition. Pt/GdFeCo films were deposited on thermally oxidized Si substrates using magnetron sputtering. The films were patterned into 5 μm × 30 μm wires by optical lithography and Ar ion milling. Current pulses were applied to the wire via a pulse generator and Kerr microscope images were captured to study current induced motion of domain walls. Figure 1 shows typical Kerr microscope images of magnetic domain walls driven by current pulses. Pulse duration dependence of the current induced domain wall velocity for Pt/GdFeCo wires with various Gd composition will be presented.