2001 Fiscal Year Final Research Report Summary
Search for Superconductivity of Magnetic Metals under Pressure
| Project/Area Number |
11304022
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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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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Osaka University |
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Principal Investigator |
AMAYA Kiichi Graduate School of Engineering Science, Osaka University, Prof., 大学院・基礎工学研究科, 教授 (80029503)
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| Co-Investigator(Kenkyū-buntansha) |
NASU Saburo Graduate School of Engineering Science, Osaka University, Prof., 大学院・基礎工学研究科, 教授 (00030057)
KOBAYASHI Tatsuo Research Center for Materials under Extreme Conditions, Osaka University, Assist. Prof., 極限科学研究センター, 助教授 (80205468)
SHIMIZU Katsuya Graduate School of Engineering Science, Osaka University, Assistant, 大学院・基礎工学研究科, 助手 (70283736)
SUZUKI Naoshi Graduate School of Engineering Science, Osaka University, Prof., 大学院・基礎工学研究科, 教授 (40029559)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Superconductivity / Ultra-high Pressure / Magnetism / Metal |
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| Research Abstract |
1. Complex condition of low temperature down to 30mK and high pressure up to 200GPa is achieved. experimental techniques for electrical, magnetic and optical measurement under extreme conditions are developed.
2. Search for superconductiyity of iron in its non - magnetic state under pressure are performed by the following procedure ; a. Purification of iron is performed in ultra high vacuum. b. Purified sample is pressed in NaCl pressure media by diamond anvil cell (DAC). c. Electrical resistance and magnetization measurement are performed in the course of both inereasing and decreasing process of pressure.
3. Results
Onset of superconductivity is found by the drop of electrical resistance and also confirmed by the detection of Meissner effect. Temperature vs pressure phase diagram is obtained. Tc appears at 15GPa just after the crystal phase transition from bcc to hep phase and disappears at 30GPa. The maximum of Tc and Hc is 2K and 2000Oe respectively.
4. Other Results
(1) Mossbauer experiment under low temperature and high magnetic field is performed and we confirmed the magnetism of iron at hep phase was due to conduction electron )pauli para magnetism).
(2) The first principle band calculation is performed and estimation of Tc is given.
(3) We have also studied the case of antiferromagnetic Mn. We found that the Neel temperature Tn disappears at around 9GPa but no sign of superconductivity is found yet even for purified sample.
(4) Pressure induced superponductiyity of ferromagnet UGe_2 is studied in detail by electrical resistance and heat capacity measurement and determined the Tc - pressure phase diagram.
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