2000 Fiscal Year Final Research Report Summary
NMR Study of Spin Dynamics of Ladder Compounds and High-Tc Superconductors
| Project/Area Number |
11694048
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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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 | Hokkaido University |
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Principal Investigator |
KUMAGAI Ken-ichi Hokkaido University, Graduate Scholl of Science, Professor, 大学院・理学研究科, 教授 (70029560)
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| Co-Investigator(Kenkyū-buntansha) |
FURUKAWA Yuji Hokkaido University, Graduate Scholl of Science, Research Associate, 大学院・理学研究科, 助手 (50280863)
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| Project Period (FY) |
1999 – 2000
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| Keywords | NMR / Ladder compounds / Spin Gap / High-Tc Cuprate Superconductor / Strongly Correlated System |
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| Research Abstract |
Hole-doping effects on the magnetism of the chain and the ladder site are investigated by Cu-NMR and NQR for single crystal of Sr_<14-x>A_xCu_<24>O_<41> (A=Ca and La). Antiferromagnetic (AF) order of Cu moments is confirmed in the chain for 3≦x≦6 of Sr_<14-x>La_xCu_<24>O_<41>. The magnetic order of Cu spins is ferromagnetic within the chain, and is antiferromagnetic for inter-chains. The field-induced staggered moments at the ladder Cu site appear fin above T_N, and its temperature dependence obeys the Curie-Weiss behavior, suggesting that this staggered field is attributed to the magnetic nature of the ladder Cu spins themselves. A possible origin is ascribed to the disturbance of the coherence of the RVB state by doping centers in the ladder. Finally a long-range AF order in the highly-doped compound of Sr_<2.5>Ca_<11.5>Cu_<24>O_<41> is discussed based on the Cu-NMR/NQR results. This AF order is responsible for the chain Cu spins.
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