[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-E202-10] Field-free spin-orbit torque magnetization switching in a perpendicularly magnetized (Ga,Mn)As single layer

〇(P)Miao JIANG¹、Chenda Wang¹、Shinobu Ohya^1,2,3、Masaaki Tanaka^1,2 (1.EEIS, Univ. of Tokyo、2.CSRN, Univ. of Tokyo、3.IEI, Univ. of Tokyo)

キーワード：field-free SOT switching, semiconductor, single layer

Nowadays, magnetic random access memory (MRAM) is proposed as one of the most promising next-generation memory technologies. For further improving the writing performance, the integration density and the efficiency, current-induced spin-orbit torque (SOT) magnetization switching has been achieved in a ferromagnet single layer with a perpendicular magnetic anisotropy (PMA). By injecting an in-plane charge current, the spins induced by the internal effective fields in the single layer can exert a torque on the magnetic moment and reverse it. However, to achieve a deterministic magnetization switching in a magnetic system with PMA, a small in-plane external magnetic field H_ext is generally necessary to break the symmetry, which limits the scalability of the SOT-MRAM devices. Therefore, achieving the field-free SOT magnetization switching in a ferromagnet single layer is strongly required because it is promising for obtaining both the high efficiency and good scalability of MRAM devices.
Here, we report a successful field-free SOT switching in a (Ga,Mn)As single layer by engineering a tilted anisotropy axis and a Mn distribution gradient along the growth direction. Our findings will advance the development of highly-efficient MRAM with better scalability.