2006 Fiscal Year Final Research Report Summary
Understanding of Mechanism for Superconductivity on f-electron Superconductors with No Inversion Symmetry by High-pressure NMR
| Project/Area Number |
17540337
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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 |
Condensed matter physics II
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| Research Institution | University of Hyogo |
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Principal Investigator |
KOHARA T. University of Hyogo, Graduate School of Material Science, Professor, 大学院・物質理学研究科, 教授 (70107986)
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| Co-Investigator(Kenkyū-buntansha) |
UEDA K. University of Hyogo, Graduate School of Material Science, Assist. Professor, 大学院・物質理学研究科, 助手 (20203440)
MOTOYAMA G. University of Hyogo, Graduate School of Material Science, Assist. Professor, 大学院・物質理学研究科, 助手 (20360050)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Low Temperature / Mechanism for Superconductivity / Nuclear Magnetic Resonance / Strongly Correlated Systems / High Pressure Properties / Non-BCS Mechanism / f-electron Superconductors / Knight Shift |
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| Research Abstract |
The purpose of this project is the following two issues : one is to get the electronic information on the superconducting energy gap appearing in the antiferromagnetic state of CePt3Si, the other is to get the microscopic superconducting character of ferromagnetic UIr under high pressure. First of all, we found the best stoichiometry of Ce, Pt and Si in CePt3Si by trial and error. After that we measured the NMR spectra for Si and Pt on the aligned sample under external field. The obtained results were not consistent with the magnetic structure reported previously by the neutron diffraction study. Next, we measured the temperature-dependence of nuclear relaxation rate for the wide temperature range on CePt3Si and non-magnetic LaPt3Si. Strangely enough, the relaxation rate of La system is higher than that of Ce system. Both important NMR results will be clearly explaned, which will be published in some journals. The temperature dependence of Knight shift through the superconducting transition temperature (Tc) was also measured. The Knight shift, namely the spin susceptibility, parallel to the c-axis did not show any change, which leads to the Cooper-pairs of odd parity in CePt3Si. Too long coherence length prevented us from finding the detailed behavior of nuclear relaxation rate just below Tc, even if performed by the field-cycling NMR. So we should try to measure again the relaxation rate with best parameters for the field-cycling measurements in the near future. Unfortunately, we could not find Ir NMR signals in UIr for the ferromagnetic and paramagnetic states, although already succeeded in finding Ir signals in other reference samples. Anyhow, both samples of CePt3Si and UIr are so important for unusual behaviors in the superconducting and normal states that we plan to perform the NMR, experiments to find interesting results for the time being. (298 words)
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Research Products
(9 results)
