| Project/Area Number |
19K21854
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 13:Condensed matter physics and related fields
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
Satoh Takuya 東京工業大学, 理学院, 教授 (40451885)
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| Project Period (FY) |
2019-06-28 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
Fiscal Year 2020: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000)
Fiscal Year 2019: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
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| Keywords | ラマン散乱 / 円偏光 / フォノン / マグノン |
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| Outline of Research at the Start |
ラマン散乱分光法は1928年の発見以来、結晶の構造、結晶を構成する原子間やイオン間の相互作用について知見を得る上で不可欠な手法であり、赤外分光法と相補的な関係にある。しかし、直線偏光を用いたラマン散乱分光法では、磁性体・誘電体結晶中のスピン波（マグノン）や格子振動（フォノン）の振動モードを探索・同定することが困難である場合も多い。
本研究では、磁性体・誘電体結晶中のマグノンやフォノンの振動モードを、円偏光を用いたラマン散乱分光法によって探索・同定する。
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| Outline of Final Research Achievements |
The optical magnon (Kaplan-Kittel exchange resonance mode) in the ferrimagnetic material YIG was observed using circularly polarized Raman scattering, and the temperature dependence of the frequency was precisely measured. From the results, the exchange interaction constant was accurately determined.
Furthermore, circularly polarized Raman scattering measurements were performed on the multiferroic material BiFeO3 to identify the mode of phonons, which had not been precisely determined. We also measured the temperature dependence of each phonon frequency and considered the possibility of spin-phonon coupling.
From the above results, one can conclude that circularly polarized Raman scattering has achieved mode detection and mode identification that could not be obtained by linearly polarized Raman scattering alone.
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| Academic Significance and Societal Importance of the Research Achievements |
円偏光を用いたラマン光学活性(ROA)は以前から知られていたが、その効果は小さく、また適用できる対象物質はキラル物質等に限られていた。円偏光ラマン散乱をモードの同定として用いるという本研究手法は原理が単純明快であり、幅広く様々な結晶に対して適用可能であるため、フォノンやマグノン振動モードの解析、マグノン探索において極めて強力な手法となるであろう。
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