1998 Fiscal Year Final Research Report Summary
NMR study of heavy fermion superconductor at low temperatur
| Project/Area Number |
09640445
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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 | Himeji Institute of Technology |
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Principal Investigator |
KOHORI Yoh Himeji Institute of Technology, Associate Professor, 理学部, 助教授 (10153660)
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| Project Period (FY) |
1997 – 1998
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| Keywords | NMR / NQR / super conductor / heavy fermion / U compound |
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| Research Abstract |
The interplay between superconductivity and magnetism in the heavy fermion (HF) superconductors is a fascinating subject. In particular, the presence of ferromagnetic (F) or antiferromagnetic (AF) spin fluctuations has led to the prediction that an unconventional Cooper pair state with non S-wave symmetry is realized in these systems. The non S-character of the superconductivity induces the power-law temperature (T) dependence of the various physical properties at low temperatures. We have performed NMR/NQR studies in URu_2Si_2 and UPd_2Al_3, and measured the nuclear spin lattice relaxation time (T_l) of ^<101>Ru, ^<29>Si, ^<105>Pd and ^<27>Al in the superconducting state. The observed T-dependence of 1/T_1's (of all nucli) is proportional to T^3, which indicated the existence of line nodes in the superconducting energy gap. In UPd_2Al_3, the decrease of ^<27>Al Knight shift was observed, which shows the superconductivity has the even parity d-wave symmetry. On the contrary, any decrease of Knight shift was not observed in URu_2Si_2. Hence the possibility of p- or f- wave superconductivity in URu_2Si_2 still remains. The accurate measurements of the single crystal URu_2Si_2 is still continuing to determine the symmetry.
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