2021 Fiscal Year Annual Research Report
二次元ファンデルワールス反強磁性体におけるスピンダイナミクスの電気的検出
| Project/Area Number |
21J20477
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| Allocation Type | Single-year Grants |
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| Research Institution | Osaka University |
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Principal Investigator |
渡邉 杜 大阪大学, 理学研究科, 特別研究員(DC1)
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| Project Period (FY) |
2021-04-28 – 2024-03-31
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| Keywords | van-der-Waals / antiferromagnet / electrical transport |
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| Outline of Annual Research Achievements |
Low dimensionality is a central topic in the field of magnetism, due to the exotic magnetic properties induced by largely enhanced fluctuations of the magnetic moments. From an experimental point of view, atomically layered magnetic materials have been gaining large attraction in recent years. These materials allow fabrication of high quality thin films even down to an atomic monolayer, and provide an ideal experimental testbed for the study of low dimensional magnetic systems. In this research theme, the applicant aims to study the detailed magnetic properties of low dimensional antiferromagnets through atomically layered magnetic materials.
This year, the applicant has focused on an atomically layered triangular antiferromagnet known as Ag2CrO2. In this material, a large butterfly-shaped hysteresis is observed in the magnetoresistance near its antiferromagnetic transition temperature, only when the material is fabricated to a thin film. This is likely due to the strong thermal fluctuations of the magnetic moments; however, the details are not fully elucidated yet. Therefore, the applicant has performed electrical transport measurements of the material up to 8 T in order to further investigate its magnetic properties. From these measurements, the applicant was able to observe a significant nonlinear Hall effect present only in the vicinity of the transition temperature, as well as extremely large linear magnetoresistance at low temperatures. These results provide further insight to the dynamics of magnetic moments in Ag2CrO2.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
In the plan for this fiscal year, the applicant aimed to perform electrical and spin transport measurements of Ag2CrO2 in order to obtain a full picture of its magnetic moment dynamics. However, several new transport properties were observed in the electrical transport measurement alone, which has led the applicant to focus on only the electrical transport during this fiscal year. These findings provide much more details of the magnetic properties of Ag2CrO2 than the applicant had initially anticipated from the electrical transport measurements. Although spin transport measurements are still necessary to obtain a fuller picture, the overall progress has been much more fruitful than what was expected initially.
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| Strategy for Future Research Activity |
In the next fiscal year, the applicant aims to perform spin transport measurements in Ag2CrO2. Meanwhile, the applicant will continue to work with external collaborators in order to understand the origin of the nonlinear Hall effect observed in Ag2CrO2, as well as the large linear magnetoresistance observed at low temperatures. These findings should provide a detailed understanding of the dynamics of thermally fluctuating magnetic moments in Ag2CrO2.
Furthermore, the applicant aims to perform measurements of CeTe3 and its Se doped counterpart. This is one of the few atomically layered materials where fluctuations of magnetic moments are enhanced through competition of two antiferromagnetic phases. Transport measurements of this material should provide further details of the magnetic moment dynamics as well as new insight towards the nature of quantum critical points.
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[Presentation] Bi/Ni薄膜の超伝導秩序変数2022
Author(s)
徳田将志, 中尾舞, 渡邉杜, 中村瞭弥, 前田将輝, Sanghyun Lee, Yue Di, 青山和司, 水島健, Jin Xiao-Feng, 小林研介, 新見康洋
Organizer
日本物理学会第77回年次大会
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