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Generation, manipulation and detection of spin currents are important issues in the operation spintronic devices because a spin current plays an important role in spin-dependent transport and spin-transfer switching. Especially, pure spin current which is the spin current without accompanying the charge current is an attractive quantity for utilizing the spin current efficiently. Nonlocal spin valve measurements in laterally configured ferromagnetic metal (FM)/nonmagnetic metal (NM) hybrid nanostructures is a powerful means for evaluating the intriguing properties of pure spin current precisely. In this talk, I will introduce materials for the efficient generation and detection of the pure spin current and a structure for efficient control of the absorption property of the pure spin current.
In the first part, I will introduce the results on the efficient generation of pure spin current using CoFeAl. We show that CoFeAl alloy is an excellent material not only for the electrical spin injection but also thermal spin injection because of its favorable band structure[1]. Further optimization for the thermal spin injection has been demonstrated
by adjusting the Co and Fe composition.[2]
In the second part, I will introduce the thermal spin injection based on the ferromagnetic resonance (FMR) heating effect. We show that the heat dissipation due to the FMR produces the temperature change over 10 K[3]. This FMR heating is found to induce sufficiently large electrical voltage by combining with inverse spin Hall effect in the ferromagnetic/nonmagnetic bilayer system[4]. The device structure for the efficient thermal spin injection is also presented.
Reference
[1] S. Hu, H. Itoh, and T. Kimura, NPG Asia Mater. 6, e127 (2014).
[2] T Nomura, T Ariki, S Hu, T Kimura, J. Phys. D: Appl. Phys. 50, 465003 (2017)
[3] K. Yamanoi, Y. Yokotani and T. Kimura, Appl. Phys. Lett. 107, 182410 (2015);
[4] K. Yamanoi, Y. Yokotani and T. Kimura, Phys. Rev. Appl. 8, 054031 (2017).
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