| Project/Area Number |
10044044
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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 Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KUMAGAI Ken-ichi Hokkaido University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (70029560)
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| Co-Investigator(Kenkyū-buntansha) |
マリ M スイス, チューリッヒ大学, 講師
ブリンクマン D スイス, チューリッヒ大学, 教授
ヤクボフスキー A ロシア, クルチャトフ研究所, 主任研究員
ボルサ F 米国, アイオワ州立大学, 教授
BRINKMANN Detlef Zurich University, Department of Physics, Switzerland, Professor
MALI Mija Zurich University, Department of Physics, Switzerland, Lecturer
BORSA Ferdinando Iowa State University, USA,Professor
YAKUBOVSKII Andrey Kurchatov Institute, Russia, Head of Scientist
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| Project Period (FY) |
1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | NMR / Oxides / High-T.superconductors / Strong correlated electron / Metal-insulator transition / spin ladder compounds / quantum spin systems |
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| Research Abstract |
In this project, unusual electronic properties of the strongly correlated systems such as ladder compounds and transition metal oxides have been investigated by NMR/NQR measurements aa well as magnetic susceptibility and heat capacity measurement. These researches were done under the collaboration of Iowa State University, Kurchatov Institute and Zurich University.
Hole-doping effects on the spin gaps for both the chain and the ladder site are investigated by Cu-NMR and NQR for single crystals of Sr_<14-x>A_1Cu_<24>O_<41> (A=Ca and La). We have confirmed longrange antiferromagnetic order of Cu moments of the chain for 3*x*6 of Sr_<14-x>La_xCu_<24>O_<41>. The experimental results indicate that the magnetic order of Cu spins in the chain is ferromagnetic within the chain, and is antiferromagnetic for the inter-chains. The field-induced staggered moments appears far above T_N. The temperature dependence of the induced field obeys the Curie-Weiss like behavior. These results suggest that the staggered field is not related to the ordered Cu chain moments but is attributed to the magnetic nature of the ladder Cu spins. Possible origins of the field-induced staggered moments at the ladder Cu site are discussed. In addition, we have investigated detail nature of the magnetic order which is observed for a highly hole-doped compound of Sr_<2.5>Ca_<11.5>Cu_<24>O_<41>.
We have also studied metal-insulator (MI) transition in some transition metal oxides. Magnetic and local electronic states near the Metal-Insulator transition have been discussed and presented in original papers We have also presented the results at the lnternational Conference on Strongly Correlated Electron Systems in France, Workshop on NMR in Elecronic Conductors, France, and Colloquium on Magnetic Resonance in High-T.Superconductors, Switzerland.
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