[22p-A205-1~18] 10.2 スピン基盤技術・萌芽的デバイス技術

▲ [22p-A205-10] Giant spin-charge interconversion efficiency originated from
the large g-factor in single crystal bismuth(110)

〇Naoki Fukumoto¹、Motomi Aoki¹、Yuki Fuseya²、Ryo Ohshima¹、Ei Shigematsu¹、Teruya Shinjo¹、Yuichiro Ando^1,3、Syoya Sakamoto⁴、Masanobu Shiga⁵、Shinji Miwa⁴、Masashi Shiraishi¹ (1.Kyoto Univ.、2.Univ. of Electro-Communications、3.PRESTO, JST、4.ISSP, Univ. Tokyo、5.Kyushu Univ.)

キーワード：bismuth, spin-orbit torque, g-factor

Despite the large spin-orbit coupling of Bi, the spin-charge interconversion (SCI) efficiency of Bi was still substantially small, which has been an open question. To obtain further understandings of the SCI of Bi, we investigated the SCI efficiency in the Bi(110) whose g-factor has known to be much larger than Bi(111). Large g-factor can realize the high spin polarization efficiently. We conducted the spin torque ferromagnetic resonance (ST-FMR) measurement and the harmonic Hall measurement that are widely used for the SOT evaluation in a variety of materials. Using electron beam deposition, Ar ion milling and a lift-off method, the Bi(110) devices for the ST-FMR and the harmonic Hall measurements were prepared. The second Harmonic signal was fitted by a conventional fitting function considering thermal effects, and the efficiency ξ_DL of Bi(110) was estimated to be +0.27. Detailed discussion including an origin of the anisotropy in the SCI efficiency of Bi is implemented in the presentation.