Spin injection from a magnetically near-compensated state in GdFeCo and inverse spin Hall effect in electron–hole compensated metal YH2

• Published in: Journal of physics. Condensed matter 2024-11, Vol.37 (6)
• Main Authors: Yamazaki, Ikuo, Koinuma, Yukihiro, Hanajiri, Tatsuro, Van Thach, Pham, Ranjbar, Sina, Sumi, Satoshi, Awano, Hiroyuki, Nakamura, Osamu, Hasegawa, Shigehiko, Sakai, Masamichi
• Format: Article
• Language: English
• Subjects: electron–hole compensated metal; GdFeCo; inverse spin Hall effect; magnetization compensation; spin accumulation; spin current
• ISSN: 0953-8984; 1361-648X; 1361-648X
• DOI: 10.1088/1361-648X/ad9371

Rare-earth-transition-metal (RE-TM) ferrimagnets are excellent materials for spin encode/decode operations via spin transport in nonmagnetic regions. This superior performance stems from two key factors. First, the antiferromagnetic coupling between RE4f and TM3d sublattices reduces both the spin-transfer-torque switching time and inter-device magnetic-coupling. Second, the RE-TM ferrimagnets function as spin injectors/ejectors, with the TM3d sublattice solely responsible for carrier spin polarization (p), similar to conventional ferromagnetic metals. We performed spin transport experiments using the sign change ofpin RE-TM, which exhibits a positive value above the magnetization compensation temperature and a negative value below it. We measured temperature dependencies of the transverse resistances (RT) of electron-hole compensated metal YH2under out-of-plane spin-polarized current injection/ejection from GdFeCo (Gd:Fe:Co = 25:66:9). The abrupt change in loop polarity of the out-of-plane field dependence ofRTin YH2between 290 and 300 K, which aligns with the out-of-field curve of the polar Kerr rotation in GdFeCo electrodes, strongly suggests that the observedRTresults from the inverse spin Hall effect (ISHE) in YH2. We analytically formulated ISHE in terms of the electron and hole spin currents injected from the spin sources, enabling regression analysis to assess the spin transport characteristics of a GdFeCo/YH2/GdFeCo magnetic double heterostructure. To explain the observed Hall voltages, enhancements in both the spin diffusion length of YH2and the spin injection efficiency are necessary.Rare-earth-transition-metal (RE-TM) ferrimagnets are excellent materials for spin encode/decode operations via spin transport in nonmagnetic regions. This superior performance stems from two key factors. First, the antiferromagnetic coupling between RE4f and TM3d sublattices reduces both the spin-transfer-torque switching time and inter-device magnetic-coupling. Second, the RE-TM ferrimagnets function as spin injectors/ejectors, with the TM3d sublattice solely responsible for carrier spin polarization (p), similar to conventional ferromagnetic metals. We performed spin transport experiments using the sign change ofpin RE-TM, which exhibits a positive value above the magnetization compensation temperature and a negative value below it. We measured temperature dependencies of the transverse resistances (RT) of electron-hole compensated metal YH2under out-of-plane spin-