2023 Fiscal Year Final Research Report
Real space observations of topological spin textures and their dynamics by electron microscopy
| Project/Area Number |
19H00660
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Medium-sized Section 13:Condensed matter physics and related fields
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
Yu Xiuzhen 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 (30538244)
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Keywords | トポロジカルスピン構造 / スキルミオン紐 / スピンヘッジホッグ構造 / 3次元磁化顕微観察 / 電流・熱流下のスキルミオンの動的挙動 |
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| Outline of Final Research Achievements |
To visualize three-dimensional (3D) topological spin textures, we developed Lorentz TEM and differential phase contrast (DPC) tomography. We demonstrated new 3D topological structures, such as skyrmion (Sk) strings, (anti)hedgehogs, and 'hopfion' in chiral-lattice magnets. The achievments allowed us to gain insights into 3D spin structures in addition to the 2D topological structures observed thus far. We achieved a spatial and temoral resolutions of less than 5 nm and 10 minutes, respectively, by using the DPC tomography, which significantly enhances the spatial and temporal resolution compared to conventional 3D magnetic imaging techniques.
Using in-situ Lorentz TEM, we generated and visualized for the first time a square lattice of Sks with a diameter of 1.9 nm in GdRu2Si2 at an ultralow temperature (8K), the smallest ever observed in known compounds. We elucidated the dynamic behavior of (anti)Sks by investigating their 'driving dynamics' in response to 'current' and 'heat flow'.
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| Free Research Field |
物性物理、顕微計測、ナノサイエンス、スピントロニクス
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| Academic Significance and Societal Importance of the Research Achievements |
従来の3次元観察では、膨大なデータセットを取得するのに時間がかかり（少なくとも数時間）、特にナノスケールの磁化構造の場合、時間だけでなく高い空間分解能も求められる。本研究では、新たに3次元電子線位相差顕微法を開発し、従来の3次元磁化イメージングの空間分解能（約10nm）を大幅に向上させ、5nm以下を達成した。さらに、測定時間も10分以下に短縮できた。また、磁気単極子を含むスキルミオンの低電流／熱流下での動的特性を明らかにした。この成果は、トポロジカル材料科学の理論構築や、将来の革新的な低消費電力デバイスに向けた概念実証に重要な役割を果たすことができた。
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