1996 Fiscal Year Final Research Report Summary
Research on highly correlated superconductor
| Project/Area Number |
08044084
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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 Faculty of Eng.Sci.Osaka Univ., 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
STEGLICH F Institute for Festkorperphysik, Technische Hochschule Darmstadt, Prof., 物理部, 教授
FLOUQUET J Center d'Etudes Nucleaires de Grenoble, Directer, 凝縮系部門, 部長
MIYAKE Kazumasa Faculty of Eng.Sci.Osaka Univ., Prof., 基礎工学部, 教授 (90109265)
AMAYA Kiichi Faculty of Eng.Sci.Osaka Univ., Prof., 基礎工学部, 教授 (80029503)
KITAOKA Yoshio Faculty of Eng.Sci.Osaka Univ., Assoc.Prof., 基礎工学部, 助教授 (70110707)
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| Project Period (FY) |
1996
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| Keywords | NMR / Highly Correlated electron system / Triplet Pair / p-Wave / Heavy Fermion / High Tc Superconductor / CeCu_2Si_2 / UPt_3 |
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| Research Abstract |
From the NMR measurements following results are obtained
1.Heavy Fermion
(1) There are two phases, S and A.coexisting with each other in CeCu_2Si_2. Both phases transform to each other with a delicate change of the Cu and Si content. S-phase is concluded to be of d-wave superconductor whose character is affected by the existence of the magnetic A phase.
(2) From the Knight shift measurement of Pt in a single crystal UPt_3, the Cooper pairis concluded to be of triplet. This is the first discovery of the triplet superconductivity. The spin orbit coupling of the Cooper pair is so weak that the spin of triplet pair orients to an external field even of about 1000G.
2.High Tc Material
(1) The increase of 1/T_1 of Cu associated with the increase of Ni content in YBa_2 (Cu, Ni)_3O_7 scales with the decrease in Tc, which is a direct evidence for the attractive force to be magnetic in origin. The decrease in Tc is attributed to the decrease of the energy of antiferromagnetic spin fluctuations.
(2) In HG system, the decrease in Tc from the 3 CuO_2 layr to 4 CuO_2 layr is attributed to the difficulty of the hole doping at the 4 fold CuO_2 plane together with the bad quality of the sample.
(3) Sr_2RuO_4 is concluded to have either p or d-wave symmetry of the Cooper pair.
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Research Products
(14 results)
