1998 Fiscal Year Final Research Report Summary
SUPERCONDUCTING STATE OF (Ce, La)Ru COMPOUNDS WITH CUBICLAVES PHASE UNDER HIGH PRESSURE
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 |
Section | 一般 |
Research Field |
固体物性Ⅱ(磁性・金属・低温)
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Research Institution | UNIVERSITY OF THE RYUKYUS |
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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Keywords | superconductivity / pressure effect / crystallographic phase transition / Cerium compounds / cubic Laves phase / tunnel electron spectroscopy / thermopower |
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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Research Products
(6 results)