| Project/Area Number |
22K14561
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 28020:Nanostructural physics-related
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| Research Institution | Keio University |
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Principal Investigator |
高 藤華 慶應義塾大学, 理工学研究科(矢上), 助教 (60896851)
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| Project Period (FY) |
2022-04-01 – 2023-03-31
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| Project Status |
Discontinued (Fiscal Year 2022)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2023: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2022: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
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| Keywords | Spin-orbit torques / Energy barrier / Spin mixing conductance / Topological semimetal / Spin Hall effect / Magnonics / 2D materials |
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| Outline of Research at the Start |
As a new class of materials, two-dimensional (2D) van der Waals (vdW) crystals with well established magnetic order are promising for efficient magnon spin transport; In this project, we aim to investigate the spin transport through vdW barriers as a magnon current medium, and clarify the relationship between magnon torque generation efficiency and exchange coupling in 2D vdw magnet.
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| Outline of Annual Research Achievements |
To develop two-dimensional van der Waals crystal based magnon spin-orbit torque devices, the first crucial step is to find an efficient spin polarization source that can be used to activate magnon spin current. By designing a metal-magnet/topological semimetal heterostructure, we find that the bulk spin Hall effect of the semimetal is sizable, leading to a high spin-orbit torque generation efficiency comparable to that in heavy metal based heterostructures. Strikingly, we show evidence that the energy barrier exists even in metal-magnet/semimetal heterojunctions, which governs spin transport manifested as a large observed field-like spin-orbit torque and thus a large imaginary part of the spin mixing conductance contrary to conventional wisdom, providing a new spin transport mechanism.
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