2023 Fiscal Year Final Research Report
Microscopic understanding of conventional spintronics materials and establishment of next-generation type spintronics mechanism through polarised neutron scattering
| Project/Area Number |
21H03732
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 80040:Quantum beam science-related
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| Research Institution | Tohoku University |
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Principal Investigator |
Nambu Yusuke 東北大学, 金属材料研究所, 准教授 (60579803)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 物性実験 / 偏極中性子散乱 / スピントロニクス / フラストレート磁性 |
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| Outline of Final Research Achievements |
We have conducted the following research topics. (1) Analytical formulae for neutron polarisation correction were derived, and the correction was actually made on the Y3Fe5O12 data. Through experiments on Tb3Fe5O12, we clearly showed that the temperature dependence of the spin current can be predictable via the information on the magnetic excitations and their temperature dependencies, as well as the magnon polarisation of the target material. (2) We refined the magnetic structures of noncentrosymmetric magnet Sr2MnSi2O7 under zero and finite magnetic fields, determined the strengths of coupling constants from inelastic scattering, and demonstrated the existence of magnon polarisation. (3) Through a polarised neutron scattering experiment on the triangular antiferromagnet NiGa2S4, we obtained decisive evidence for a binding-unbinding transition of vector chirality vortices. The temperature dependence of spin relaxation time was also traced over 13 orders of magnitude for FeGa2S4.
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| Free Research Field |
物性物理学
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| Academic Significance and Societal Importance of the Research Achievements |
従来型スピントロニクスにおいて、これまでは電圧測定に限られることが多数であった。今回の成果によってスピントロニクスにおける微視的知見に基づくアプローチが確立され、今後は磁気励起情報に基づく高効率スピン流伝播物質の選定が進むことが想定される。また、カイラリティ等の高次スピン自由度に基づく物性は磁性研究の分野で注目されているが、実験的傍証に留まっている。今回の実験でスピン空間における異方性や（Q, E）分解した情報を理論計算と合わせることで、より直接的な証拠を得るに至った。本研究で実証した新偏極中性子散乱手法は微視的視点から電子自由度の理解を深め、他の自由度への応用でも一定の波及効果が期待される。
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