NMR Study on the Strong Electron Correlations in Superconducting Cu Spinel Sulfides
Grant-in-Aid for Scientific Research (B)
|Allocation Type||Single-year Grants|
|Research Institution||KOBE UNIVERSITY|
WADA Shinji Kobe University, Faculty of Sciences, Professor, 理学部, 教授 (00031360)
|Project Period (FY)
1996 – 1998
Completed(Fiscal Year 1998)
|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1998 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1997 : ¥1,800,000 (Direct Cost : ¥1,800,000)
|Keywords||Cu Spinel sulfides / itinerant weakly antiferromagnetism / superconductivity / electron correlations / Structural phase transition / 超伝導と磁性 / 核磁気共鳴 / 強相関電子物性 / 遍歴型反強磁性 / スピネル硫化物|
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.
Research Output (26results)