Realization of vortex spin current by spin injection into superconductors

2015 Fiscal Year Final Research Report

• Project/Area Number: 26610091
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Tohoku University
• Principal Investigator: SHIOMI Yuki 東北大学, 金属材料研究所, 助教 (10633969)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 超伝導 / ボルテックス / スピン流 / スピントロニクス / 量子渦

Outline of Final Research Achievements

In type-II superconductors, superconducting vortices appear by penetration of external magnetic fields in superconductors. In this study, we aim to realize a novel spin current using the flow of superconducing vortices. The samples are bilayers of s-wave superconductor|ferromagnet and d-wave superconductor|ferromagnet. By applying temperature gradient or microwaves to the ferromagnetic layer, spin current was injected from the ferromagnet to the adjacent superconductor. The vortex spin current in superconductors was measured via a spin-to-charge conversion effect in superconductors. As a result, we observed an electric signal in superconducting states, which was never observed in normal states. From additional experiments, we showed that this electric signal observed only in superconducting states is related to dynamics of superconducting vortices. We have discussed microscopic mechanisms of this novel effects.

Free Research Field

スピントロニクス