| Project/Area Number |
06044135
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Osaka University |
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Principal Investigator |
ASAYAMA Kunisuke Osaka Univ., Faculty of Eng. Sci., Prof., 基礎工学部, 教授 (20029416)
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| Co-Investigator(Kenkyū-buntansha) |
COQBLIN B. Recherches au C.N.R.S., Orsay, Directer, ディレクター
BERTHIR C. Lab. Spectrometrie Physique, Univ. J.F.Grenoble, Prof., 光学研究所・NMR部門, 主任研究員
STEGLICH F. Technische Hochschule Darmstadt, Institut fur Festkorperphysik, Prof., 物理部, 教授
FLOUQUET J. Center d'Etudes Nucleaires de Grenoble, Directer, 凝縮系部門, 部長
MAYAKE Kazumasa Osaka Univ., Faculty of Eng. Sci., Prof., 基礎工学部, 教授 (90109265)
KATAOKA Yoshio Osaka Univ., Faculty of Eng. Sci., Assoc. Prof., 基礎工学部, 助教授 (70110707)
FLOUGUET J. グルノーブル原子核研究センター, 凝縮系部門, 部長
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥10,600,000 (Direct Cost: ¥10,600,000)
Fiscal Year 1995: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 1994: ¥6,000,000 (Direct Cost: ¥6,000,000)
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| Keywords | NMR / Heavy Fermion / Superconductor / High Tc Cuprate / p-Wave / d-Wave / Spin Fluctuation / d波対 / 反強磁性 / URu_2Si_2 / UPd_2Al_3 / UNi_2Al_3 |
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| Research Abstract |
Study of highly correlated materials, heavy fermion superconductors and high Tc cuprate superconductor were carried out in collaboration with French and German researchers.
The works in both sides are complementary to each other, that is, in Japan the investigations are mainly made by NMR technique, while in Europe, sample preparation, susceptibility, electric resistivily and specific heat measurements are performed.
In 1994 4 Japanese researches visited Europe, United States and Korea and in 1995 4 Japanese visited Europe, United states and India to make collaboration work, discussions, and to exchange and collect the informations.
On the other hand, we invited 2 French researchers in 1994 and 2 German and 2 French researchers in 1995 to make collaboration work and discussions, to exchange the information and to summarize the results.
The results are as following
The ground state in CeCu_2Si_2 is non-magnetic and d wave superconducting. With slight change of the atomic configuration, the superconductivity is easily destroyed and a magnetic order appears. The nature of this magnetic order is still not clear.
UPd_2Al_3 is a d-wave superconductor probably induced by antiferromagnetic spin fluctuations where the gap zero on line is realized as observed by NMR.The specific heat measurement shows as if the gap disappears on points. The discrepancy between these measurements are attributed to a pair breaking effect which produces point zero gap like behavior even in the line zero gap state.
UPt_3 is concluded to be a p-wave superconductor induced by ferromagnetic spin fluctuations.
NMR results in Tl_2Ba_2Ca_2Cu_3O_<10> and HgBa_2Ca_2Cu_3O_8 with highest Tc show that the antiferromagnetic spin fluctuation mediated mechanism is the most promising model for the occurrence of the high Tc superconductivity.
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