Spin wave non-reciprocity in magnonic crystals

2024 Fiscal Year Final Research Report

• Project/Area Number: 21K13886
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Yamamoto Kei 国立研究開発法人日本原子力研究開発機構, 原子力科学研究所 先端基礎研究センター, 副主任研究員 (10746811)
• Project Period (FY): 2021-04-01 – 2025-03-31
• Keywords: 磁性体 / スピン波 / 非線形性 / 表面弾性波

Outline of Final Research Achievements

In this project, we aimed at understanding non-reciprocity and related phenomena of spin wave in nano structures, with a particular focus on spin wave non-linearity and control of surface acoustic waves using magnonic crystals. Through collaborations with several experimental groups both in Japan and abroad, we were able to discover new phenomena arising from Suhl instability that qualitatively alter the spectral shapes and magnetic relaxation rates with comprehensive theoretical descriptions, and succeeded in generating non-reciprocal propagation and diffraction of surface acoustic waves by fabricating appropriate magnonic crystals. These results were published in high impact journals and let to invited talks in international workshops. Along the way, they evolved into new research topics such as non-reciprocity of antiferromagnetic spin waves and magnetisation dynamics and fluctuations far from equilibrium, which are currently under way.

Free Research Field

理論物理学、スピントロニクス

Academic Significance and Societal Importance of the Research Achievements

これらの研究成果の多くは、従来知られていた現象の範囲では説明できない新しい視点をもたらす発見であり、スピン波の基礎研究とそのスピントロニクス応用に大きな影響を与える結果である。特にスピン波の非線形現象は1960年代、及び80年代に詳しく調べられたが、現代の微細加工と測定技術によってそれらの新たの側面を開拓できることが明らかになった。これらの新現象はマイクロ波を応用した電気信号制御に新たな選択肢を与える可能性がある。表面弾性波の非相反性をマグノニック結晶で制御できることを原理的に示した事は、新しい原理に基づくマイクロ波センサーやアイソレータの探求に影響を与える可能性がある。