[18a-D704-1~11] 10.2 スピン基盤技術・萌芽的デバイス技術

▼ [18a-D704-7] Research on Spin Hall Angle in CuBi Alloys by Spin Torque Measurement

〇(B)Katsuhiro Tatsuoka¹、Ryo Ohshima^1,2、Yuichiro Ando^1,2、Masashi Shiraishi^1,2 (1.Kyoto Univ.、2.CSRN, Kyoto Univ.)

キーワード：spintronics, CuBi, spin Hall angle

Cu has small spin-orbit interaction (SOI) and is known as a material with small spin Hall angle (SHA). Meanwhile, large SHA of -0.24 was measured in the Cu_99.5Bi_0.5 alloy at 10 K using a spin absorption method (Y. Niimi et al.). This observation signifies that a characteristic of the large SOI of Bi manifests in the alloy consisting mainly of a ubiquitous and low-resistive material, Cu, which is significant for practical applications such as spin-orbit torque (SOT) devices. In this study, we investigated the damping-like spin torque efficiency of Cu_99.5Bi_0.5 by using the second harmonic Hall measurement and spin torque ferromagnetic resonance measurement (STFMR) from a viewpoint of SOT device applications. From the theoretical fitting considering a thermal contribution, the SHA of the Cu_99.5Bi_0.5 is estimated to be about 0.1. In addition, it is confirmed that the sign of the SHA is positive from STFMR measurements.