[21a-131-1~11] 10.4 Semiconductor spintronics, superconductor, multiferroics

[21a-131-2] Spin-current coherence peak in superconductor/magnet junctions

〇Maki Umeda¹, Yuki Shiomi³, Takashi Kikkawa¹, Tomohiko Niizeki⁴, Jana Lustikova¹, Saburo Takahashi^1,4,5, Eiji Saitoh^2,4,5,6 (1.IMR, Tohoku Univ., 2.Dept. of Applied Phys., Univ. of Tokyo, 3.QPEC, Univ. of Tokyo, 4.AIMR, Tohoku Univ., 5.CSRN, Tohoku Univ., 6.ASRC, JAEA)

Keywords:spintronics, superconductor, heat flow

The spin current flowing across the N/F interface generated by spin pumping reflects spin susceptibilities of both layers. The injected spin current into the N layer is converted into charge current by inversed spin Hall effect (ISHE). Hence, ISHE voltage may reflect the spin dynamics of spin-detection layers.
In this study, We have investigated the ISHE induced by longitudinal spin Seebeck effects in superconductor/ferrimagnet (S/F) bilayer comprising an s-wave superconductor NbN and a ferrimagnetic insulator Y3Fe5O12 for thermal spin injection. Just below the superconducting transition temperature (Tc), the generated ISHE voltage exhibits an anomalous enhancement. Our theoretical calculation based on the linear response theory shows that the voltage enhancement is consistent with a coherence peak effect, which is unique in full-gap superconductors. The present results indicate that the ISHE may be another good method for the detection of the coherence peak.