1998 Fiscal Year Final Research Report Summary
NMR Study on the Strong Electron Correlations in Superconducting Cu Spinel Sulfides
| Project/Area Number |
08454097
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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 | KOBE UNIVERSITY |
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Principal Investigator |
WADA Shinji Kobe University, Faculty of Sciences, Professor, 理学部, 教授 (00031360)
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| Project Period (FY) |
1996 – 1998
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| Keywords | Cu Spinel sulfides / itinerant weakly antiferromagnetism / superconductivity / electron correlations / Structural phase transition |
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| Research Abstract |
1. Coexistence of the superconductivity with itinerant weakly antiferromagnetism in CuCo2SィイD24ィエD2
A coherence peak and an exponential temperature dependence of the spin-lattice relaxation rate observed in the superconducting state indicate that the system belongs to a group of a s-wave superconductors. It is confirmed microscopically that the itinerant weakly-antiferromagnetism coexists with the superconductivity.
2. Itinerant weakly antiferromagnetism in (Cu, Co) CoィイD22ィエD2SィイD24ィエD2 system
We found that the itinerant weakly antiferromagnetism originating from the A-sites appears in both the Cu-rich and the Co-rich regions, while the superconductivity appears in the limit of the Cu-rich region.
3. Structural phase transition and temperature-induced magnetism in CuVィイD22ィエD2SィイD24ィエD2
The anomalies that have been observed below 90 K in many physical quantities are well explained by the change in the electronic state of V3+ associated with a structural transition at 90 K from the high-temperature cubic phase to a low-temperature tetragonal phase.
4. Itinerant weakly magnetism in CuTiィイD22ィエD2SィイD24ィエD2
The low temperature susceptibility, specific heat, and NMR measurements indicate that CuTiィイD22ィエD2SィイD24ィエD2 is not a simple Pauli paramagnet but belongs to a group of itinerant weakly antiferromagnets, and exhibits somewhat long-range order below 5K.
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