Spin-induced weak-link device and physics

Research Project

Project/Area Number	18K18870
Research Category	Grant-in-Aid for Challenging Research (Exploratory)
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 21:Electrical and electronic engineering and related fields
Research Institution	Nagoya University
Principal Investigator	Yamashita Taro 名古屋大学, 工学研究科, 准教授 (60567254)
Project Period (FY)	2018-06-29 – 2021-03-31
Project Status	Completed (Fiscal Year 2020)
Budget Amount *help	¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000) Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2019: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000) Fiscal Year 2018: ¥2,990,000 (Direct Cost: ¥2,300,000、Indirect Cost: ¥690,000)
Keywords	超伝導デバイス / 近接効果 / 超伝導 / 磁性体 / スピントロニクス / ナノ構造
Outline of Final Research Achievements	We studied spin-induced weak-link devices which consist of the superconductor/ferromagnet bilayer. In the measurement of the temperature dependence of the resistance, we observed two-step superconducting transition indicating clearly the local suppression of the superconductivity of the superconducting wire. We investigated the effect of the ferromagnet region on the superconducting critical current and found that the variation of the critical current between the samples increased with increasing the ferromagnet area. From the present study, we obtained the new insight on physical mechanisms in the ferromagnet/superconductor bilayer structures.
Academic Significance and Societal Importance of the Research Achievements	本研究を通じて、国内外でほとんど報告例のないスピン誘起ウィークリンク素子に関する物理的知見が得られた。微小な磁性体を超伝導ワイヤに付加することで、超伝導性がどの程度の領域に渡り抑制されるのかを明らかにした他、超伝導体内でのスピン拡散や磁束ピンニングとの関連が予想される振る舞いが明らかとなり、未解明な点が多い磁性体と超伝導体の界面において生じる物理メカニズムに関する有用な知見が得られた。