| Project/Area Number |
09640441
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | UNIVERSITY OF THE RYUKYUS |
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Principal Investigator |
YAGASAKI Katsuma UNIVERSITY OF THE RYUKYUS FACULTY OF SCIENCE,PROFESSOR, 理学部, 教授 (70045037)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMA Takao UNIVERSITY OF THE RYUKYUS FACULTY OF SCIENCE,ASSISTANT PROFESSOR, 理学部, 講師 (80264472)
NIKI Haruo UNIVERSITY OF THE RYUKYUS FACULTY OF SCIENCE,PROFESSOR, 理学部, 教授 (80145549)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | superconductivity / pressure effect / crystallographic phase transition / Cerium compounds / cubic Laves phase / tunnel electron spectroscopy / thermopower |
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| Research Abstract |
1) The tunnel electron spectrography revealed that the superconducting property of CeRu_2 is strongly coupled BCS type.
2) The superconducting transition temperature T0 of CeRu_2 decreases with pressure up to 0.5 Gpa but increases above it until the pressure goes up to 5.5GPa where the pressure induced phase transition occurs. In the induced phase, T_c decreases sharply.
3) X ray measurements were performed under high pressure and revealed the transition is structural one, however the structure type cannot be confirmed yet.
4) The resistivity of CeRu_2 depends on T^2 at low temperature. The density of state at Fermi level deduced from the coefficients of T^2 dependence has just opposite pressure dependence as T_c.
5) Pressure dependence of T_c and DOS of LaRu^2 decrease with increasing pressure up to 8GPa.
6) LaRu2 and Ce_<0.8>La_<0.2>Ru_2 do not have a pressure induced phase transition up to 8GPa.
7) DOS at the Fermi level of Ce_<1-X>La_XRu_2 deduced from the resistivity shows a deep minimum around x= 0.2 just like as composition dependence of T_c.
8) The thermopower was measured on Ce_<1-X>La_XRu_2. I t appeared that the shape of the Fermi level is divided into tow groups around x = 0.5.
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