2019 Fiscal Year Final Research Report
Development and application of the technique of high sensitive magnetostrsiction measurements in high magnetic fields
| Project/Area Number |
17K05534
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
榊原 俊郎 東京大学, 物性研究所, 教授 (70162287)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | パルス磁場 / 磁歪 / キャパシタンス法 / 数値位相検波 / Bi |
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| Outline of Final Research Achievements |
In the present study, we have realized higher sensitivity of magnetostriction measurement by capacitance method in pulsed magnetic field, and attempted to measure highly conductive pure metals and candidate substances of topological insulators by using it. Although the vertical resolution has been improved by optimizing the measuring instruments and introducing numerical phase detection technique, the planned measurement of the substance was unsuccessfull due to the heat generated by the induced electromotive force accompanying the magnetic field sweep. In this measurement, unlike the transport measurement and the like, it became clear that the thermal contact of the sample is weakened because the sample space needs to be vacuum, and it is difficult to eliminate the influence of the temperature change due to sweeping magnetic fields. From these results, we have found that longer-pulsed-magnetic fields would be effective for magnetostriction measurement by the capacitance method.
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| Free Research Field |
低温強磁場物性、強相関電子物性、磁性
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| Academic Significance and Societal Importance of the Research Achievements |
本研究課題における当初目的は達成できなかったものの、その過程で信号処理技術の基幹である数値位相検波法が飛躍的に進歩した。これらは研究代表者三田村により２本の国際特許として出願されている。この方法は、交流測定において変調周波数を上げられない場合に如何に時間分解能を確保するかを突き詰めたもので、様々な分野への応用が期待できる。例えば、現状で携帯電話や地上波デジタル放送、ブロードバンド通信などで複数の周波数成分の復調に使われている直交多重周波数分割法（ＯＦＤＭ法）よりも原理的に高速での信号分離が可能であることが明らかになっており、より高い密度でのデータ送受信を可能にすると考えられる。
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