| 研究課題/領域番号 |
19J21720
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| 研究機関 | 東京大学 |
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研究代表者 |
許 明然 東京大学, 新領域創成科学 研究科, 特別研究員(DC1)
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| 研究期間 (年度) |
2019-04-25 – 2022-03-31
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| キーワード | Magnon / Phonon / Surface acoustic wave / Magnetoelastic wave / Spin wave |
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| 研究実績の概要 |
Magnon and phonon are different quasiparticles with their own attractive advantages and individual disadvantages on building future electronics. Magnon has tremendous application but short decay length. On the contrary, phonon has long decay length but limited functionalities. Magnon phonon hybridized system presents features inherited from magnon and phonon, showing long decay length in millimeters and versatile functionalities. In recent years, with the development of technology and further extended knowledge, the magnon phonon coupling(MPC) study focuses on the interaction of surface acoustic waves with a magnetic thin film. Interestingly, in this situation, where trivial magnon couples to trivial surface phonon state, there emerges nontrivial consequence of MPC, nonreciprocity.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Up to now, we have achieved highly efficient spin current generation using magnon-phonon coupling, giant nonreciprocity in a magnon-phonon hybrid system. Both are of great potential for future electronics. The efficient spin current generation may enable the integration with a memory device, while nonreciprocal transport is of great potential for replacing high-frequency microwave isolator, which is widely used in digital communication. In addition to the previous, probing the Dzyaloshinskii-Moriya interaction constant is also achieve by magnon-phonon hybridized system. Recently, by anti-crossing of spin-wave and elastic wave dispersion, we achieve zero group velocity of elastic wave, which, consequently, stops propagation and functions as an acoustic switch.
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| 今後の研究の推進方策 |
For either magnonic or phononic circuits, a nonreciprocal device is an essential element. For further study on magnon-phonon coupling, we will work on controlling the nonreciprocity. From the previous study, we concluded that MPC nonreciprocity mainly depends on the ratio between magneto-rotation coupling (MRC) and magnetoelastic coupling (MEC). Thus, in principle, by controlling the MEC, it is possible to modulate the magnitude and sign of the nonreciprocity. From the literature, we found that MEC of nickel and iron alloy highly depend on its composition ratio. This system is fairly an ideal platform for examining the influence of MRC in nonreciprocity and realizing nonreciprocity modulation.
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