| 研究領域 | 量子液晶の物性科学 |
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| 研究課題/領域番号 |
20H05164
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| 研究種目 |
新学術領域研究(研究領域提案型)
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| 配分区分 | 補助金 |
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| 審査区分 |
理工系
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| 研究機関 | 青山学院大学 |
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研究代表者 |
孫 悦 青山学院大学, 理工学部, 助教 (30824180)
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| 研究期間 (年度) |
2020-04-01 – 2022-03-31
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| 研究課題ステータス |
中途終了 (2021年度)
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| 配分額 *注記 |
5,850千円 (直接経費: 4,500千円、間接経費: 1,350千円)
2021年度: 2,990千円 (直接経費: 2,300千円、間接経費: 690千円)
2020年度: 2,860千円 (直接経費: 2,200千円、間接経費: 660千円)
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| キーワード | depairing Jc / FeSe / FIB fabrication / nematicity / superc onductivity / micro-fabrication / nematic phase / superconductivity / FIB |
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| 研究開始時の研究の概要 |
The micro-fabrication technique will be applied to reduce the size of crystal into single domain, and control the shape and geometry for the study of superconductivity and nematicity. In the fabricated devices, transport measurements will be performed to study nematicity, in the whole temperature region from the normal state (e.g. resistivity and magnetoresistance) to the superconducting state (e.g. depairing Jc). Our research will overcome the difficulty of controlling the sample's shape and direction, and open a new route to probe the relation between nematicity and superconductivity.
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| 研究実績の概要 |
We sucessfully achieved the depairing Jc in a narrow bridge of FeSe single crystal fabricated by the FIB pick-up technique. Width of the narrow bridge is reduced in sequence from 1.125 μm to 0.388 μm, which is larger and smaller than the value of Pearl length (Λ ~ 0.62 μm), respectively. Jc is directly estimated from the transport current-voltage measurements, which reaches a very large value about one order of magnitude larger than the depinning Jc estimated from the magnetic hysteresis loops (MHLs). Furthermore, the value of Jc is found to be increased more than twice simply by reducing W from 1.125 μm to 0.388 μm, which supports the achievement of depairing Jc. We also measured the Jc under magnetic fields. Jc of the narrow bridge is found to be much stable against magnetic field than that of the bulk sample. The field-insensitive Jc can be understood by the large increase of lower critical field, Hc1, when W is reduced to be comparable to λ
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| 現在までの達成度 (段落) |
令和3年度が最終年度であるため、記入しない。
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| 今後の研究の推進方策 |
令和3年度が最終年度であるため、記入しない。
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