| Project/Area Number |
15K05146
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Shimane University |
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Principal Investigator |
Fujiwara Kenji 島根大学, 総合理工学研究科, 教授 (50238630)
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| Project Period (FY) |
2015-10-21 – 2018-03-31
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| Project Status |
Completed (Fiscal Year 2017)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2016: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2015: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
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| Keywords | 超伝導 / 重い電子系 / 圧力効果 / 強磁場 / 核磁気共鳴 / 高圧 / NMR / 価数揺らぎ / 磁場誘起転移 / 強磁場誘起価数転移 |
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| Outline of Final Research Achievements |
Cu-NMR of heavy fermion superconductor CeCu2Si2 was performed under high pressure (5.4, 6.2 and 7.0 GPa) and high field (5～22 T). Ce valence and spin state were investigated by electric field gradient (EFG) at Cu sites, and by Knight Shift (K) and nuclear spin lattice relaxation time (T1), respectively. Above 5 GPa, EFG, K and 1/T1 decrease below identical temperature (T*). These behavior suggest that new crossover with valence change occurs below T*. T* monotonically increases with applying pressure (ex. T*=20, 40, 55K at 5.4, 6.2 and 7.0 GPa). Furthermore, T* is independent of magnetic field between 7 and 22 T. Therefore, the crossover at T* field induced valence transition does not result from field induced valence transition predicted by valence fluctuation model.
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