Spin currents, which are excited in indium tin oxide(ITO)/yttrium iron garnet(YIG) by the methods of spin pumping and spin Seebeck effect, are investigated through the inverse spin Hall effect(ISHE). It is demonstrate...Spin currents, which are excited in indium tin oxide(ITO)/yttrium iron garnet(YIG) by the methods of spin pumping and spin Seebeck effect, are investigated through the inverse spin Hall effect(ISHE). It is demonstrated that the ISHE voltage can be generated in ITO by spin pumping under both in-plane and out-of-plane magnetization configurations.Moreover, it is observed that the enhancement of spin Hall angle and interfacial spin mixing conductance can be achieved by an appropriate annealing process. However, the ISHE voltage is hardly seen in the presence of a longitudinal temperature gradient. The absence of the longitudinal spin Seebeck effect can be ascribed to the almost equal thermal conductivity of ITO and YIG and specific interface structure, or to the large negative temperature dependent spin mixing conductance.展开更多
Spin pumping in yttrium-iron-garnet（YIG）/nonmagnetic-metal（NM） layer systems under ferromagnetic resonance（FMR） conditions is a popular method of generating spin current in the NM layer.A good understanding of t...Spin pumping in yttrium-iron-garnet（YIG）/nonmagnetic-metal（NM） layer systems under ferromagnetic resonance（FMR） conditions is a popular method of generating spin current in the NM layer.A good understanding of the spin current source is essential in extracting spin Hall angle of the NM and in potential spintronics applications.It is widely believed that spin current is pumped from precessing YIG magnetization into NM layer.Here,by combining microwave absorption and DC-voltage measurements on thin YIG/Pt and YIG/NM_1/NM_2（NM_1 =Cu or Al,NM_2 =Pt or Ta）,we unambiguously showed that spin current in NM,instead of from the precessing YIG magnetization,came from the magnetized NM surface（in contact with thin YIG）,either due to the magnetic proximity effect（MPE） or from the inevitable diffused Fe ions from YIG to NM.This conclusion is reached through analyzing the FMR microwave absorption peaks with the DC-voltage peak from the inverse spin Hall effect（ISHE）.The voltage signal is attributed to the magnetized NM surface,hardly observed in the conventional FMR experiments,and was greatly amplified when the electrical detection circuit was switched on.展开更多
基金Project supported by the National Key Basic Research Project of China(Grant No.2016YFA0300600)Chinese Academy of Sciences(Grant No.KJCX2-YW-W24)+1 种基金the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.11604375)the Laboratory of Microfabrication of Institute of Physics,Chinese Academy of Sciences
文摘Spin currents, which are excited in indium tin oxide(ITO)/yttrium iron garnet(YIG) by the methods of spin pumping and spin Seebeck effect, are investigated through the inverse spin Hall effect(ISHE). It is demonstrated that the ISHE voltage can be generated in ITO by spin pumping under both in-plane and out-of-plane magnetization configurations.Moreover, it is observed that the enhancement of spin Hall angle and interfacial spin mixing conductance can be achieved by an appropriate annealing process. However, the ISHE voltage is hardly seen in the presence of a longitudinal temperature gradient. The absence of the longitudinal spin Seebeck effect can be ascribed to the almost equal thermal conductivity of ITO and YIG and specific interface structure, or to the large negative temperature dependent spin mixing conductance.
基金Project supported by the National Basic Research Program of China(Grant Nos.2015CB921502 and 2013CB922303)the National Natural Science Foundation of China(Grant Nos.11474184,116627805,and 11504203)+2 种基金the 111 Project(Grant No.B13029)Zhang Yin and Wang Xiangrong were supported by the Hong Kong RGC Grants(Grant Nos.16301816 and 605413)Wu Yong and Jiang Yong were supported by the National Natural Science Foundation of China(Grant No.51501007)
文摘Spin pumping in yttrium-iron-garnet（YIG）/nonmagnetic-metal（NM） layer systems under ferromagnetic resonance（FMR） conditions is a popular method of generating spin current in the NM layer.A good understanding of the spin current source is essential in extracting spin Hall angle of the NM and in potential spintronics applications.It is widely believed that spin current is pumped from precessing YIG magnetization into NM layer.Here,by combining microwave absorption and DC-voltage measurements on thin YIG/Pt and YIG/NM_1/NM_2（NM_1 =Cu or Al,NM_2 =Pt or Ta）,we unambiguously showed that spin current in NM,instead of from the precessing YIG magnetization,came from the magnetized NM surface（in contact with thin YIG）,either due to the magnetic proximity effect（MPE） or from the inevitable diffused Fe ions from YIG to NM.This conclusion is reached through analyzing the FMR microwave absorption peaks with the DC-voltage peak from the inverse spin Hall effect（ISHE）.The voltage signal is attributed to the magnetized NM surface,hardly observed in the conventional FMR experiments,and was greatly amplified when the electrical detection circuit was switched on.
