| 研究課題/領域番号 |
21F21774
|
|---|
| 研究機関 | 国立研究開発法人理化学研究所 |
|---|
研究代表者 |
大谷 義近 国立研究開発法人理化学研究所, 創発物性科学研究センター, チームリーダー (60245610)
|
|---|
| 研究分担者 |
LYONS THOMAS 国立研究開発法人理化学研究所, 創発物性科学研究センター, 外国人特別研究員
|
|---|
| 研究期間 (年度) |
2021-11-18 – 2024-03-31
|
| キーワード | magnon-phonon coupling / spintronics / magnonics |
|---|
| 研究実績の概要 |
Work commenced in December 2021. Since then, multiple new samples have been fabricated consisting of antiferromagnetic chromium trichloride (CrCl3) exfoliated flakes on top of lithium niobate (LiNbO3) piezoelectric substrates with lithographically defined interdigital transducers, allowing generation and detection of surface acoustic waves (SAWs). Resonant coupling between SAWs and the acoustic magnon mode of CrCl3 has been demonstrated at 1.1GHz, representing a first step towards the study of magnon-phonon coupling in van der Waals magnetic materials. The absorption of SAWs by the CrCl3 indicates excitation of magnons, and is observed to disappear upon heating the sample towards the Neel temperature, likely confirming the dependence on magnetic order.
|
| 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
The initial objective of the fellowship has been achieved, that is, magnon excitation by SAW irradiation in van der Waals antiferromagnetic material. However, this result has been achieved much later than anticipated, owing to an unforeseen low temperature response of LiNbO3 acoustic devices. This has caused significant problems in terms of reproducibility, with only a small percentage of fabricated samples showing the magnon-phonon coupling behaviour in experiments. Despite causing delays, the low temperature issues are being actively investigated and ways to circumvent the problems have been devised. Alternative piezoelectric substrates, quartz and aluminium nitride (AlN) wafers have been purchased to replace LiNbO3, which will hopefully alleviate the reproducibility concerns.
|
| 今後の研究の推進方策 |
The short-term plan is two-pronged. 1. Alternative acoustic devices will be fabricated using quartz and AlN substrates, and their low temperature response to GHz-range acoustic driving will be assessed for suitability for magnon-phonon coupling experiments. 2. Further work will be carried out on currently working LiNbO3 CrCl3 devices. They will be measured in a vector magnet system capable of performing a magnetic field angle dependence study, which will provide new information on the nature of the magnon-phonon interaction. Later, magnon-phonon strong coupling will be studied with CrCl3 in acoustic cavities. Otherwise, a collaboration with the University of Exeter, UK (I. Luxmoore) will begin, aiming to achieve acoustic control of colour centres in hexagonal boron nitride flakes.
|
