| Project/Area Number |
10440114
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Nihon University |
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Principal Investigator |
TAKAHASHI Hiroki Nihon University, College of Humanities and Sciences, Associate Professor, 文理学部, 助教授 (80188044)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANISHI Takeshi Nihon University, College of Humanities and Sciences, Research Associate, 文理学部, 助手 (70297761)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 1999: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1998: ¥6,300,000 (Direct Cost: ¥6,300,000)
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| Keywords | high-T_C superconductor / high pressure / diamond anvil / metal-insulator transition / spin-ladder material / ダイヤモンドアンビルセル / 遷移金属酸化物 / 遷移金属化合物 / 超伝導 |
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| Research Abstract |
Recently great attention has been paid for high-pressure research. The advantage of high-pressure research is to make continuous change of sample volume without introducing randomness effect which is often caused by alloying and/or atom substitution. In addition that recent reports on the large pressure effects on magnetism and superconductivity stimulate a lot of investigators. On the other hand, recent developments of high-pressure technique support significantly these studies.
In this project, we built a high-pressure experiment system using a diamond anvil cell (DAC) which can generate very high pressure, in which AC susceptibility and electrical resistivity measurements are designed. Our target pressure range is 10 GPa to 100 GPa. Using this system we studied superconducting transition, insulatormetal transition, and magnetic transition. Novel quantum transitions are expected to be discovered. The DAC are made from non-magnetic Cu-Be alloy and driven by pneumatic system to keep constant pressure at low temperature. Pressure in the DAC is estimated from the shift of fluorescence spectrum of ruby included in the high-pressture space in DAC.For this measurement microscopic optical analyzing system is built. AC susceptibility measurement system is also built. Special care is taken for detecting very small signal from the sample which placed in the very small high-pressure space.
In this work we successfully observed the superconducting transition of lead as a standard material placed in the DAC by AC susceptibility measurement. We also studied spin-ladder oxide systems under high pressure using conventional large volume high-pressure apparatus as a preparation to study our DAC system. The spin-ladder system is known to be a key material of high-T_C superconductors. However, superconductivity in the spin-ladder system has been observed only at high pressure. So discovery of new superconducting materials is expected in the high-pressure reserch.
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