2004 Fiscal Year Final Research Report Summary
STUDY ON SCATTERING OF CONDUCTION ELECTRONS FOR SPIN-FLUCTUATION MEDIATED SUPERCONDUCTOR VIA dHvA EFFECT
| Project/Area Number |
15540327
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
OCHIAI Akira TOHOKU UNIVERSITY, CENTER FOR LOW TEMPERATURE SCIENCE, ASSOCIATE PROFESSOR, 極低温科学センター, 助教授 (90183772)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Haruyoshi TOHOKU UNIVERSITY, CENTER FOR LOW TEMPERATURE SCIENCE, PROFESSOR, 極低温科学センター, 教授 (60302246)
KIMURA Noriaki TOHOKU UNIVERSITY, CENTER FOR LOW TEMPERATURE SCIENCE, RESEARCH ASSOCIATE, 極低温科学センター, 助手 (30292311)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Spin fluctuation / de Haas-van Alphen effect / Strongly correlated electron system / Superconductivity / Heavy Fermion / Itinerant ferromagnet / Quantum critical point / Fermi surface |
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| Research Abstract |
Scattering lifetime and effective mass of the conduction electrons for the spin-fluctuation mediated superconductor have been investigated by the de Haas-van Alphen (dHvA) effect. We selected typical compounds ZrZn_2 and CeIn_3 for the itinerant ferromagnet and magnetically ordering heavy Fermion system, respectively, both showing the unconventional superconductivity.
Pressure study of dHvA effect on ZrZn_2 revealed"nested"ferromagnetic pressure-magnetic field phase diagram being similar to that of UGe_2. However, no significant changing of the scattering lifetime and the effective mass across the phase boundary was observed in ZrZn_2. Such a feature is different from that of UGe_2 in which drastic changing of the effective mass is observed. These results suggest that the conduction electron is more sensitive for the spin fluctuation through the felectron than the d-electron.v
The dHvA frequency and the effective mass of CeIn_3 change in behavior at distinct four pressures. These successive evolutions of the conduction electron properties are quite different from the sudden changes of them observed in sister compound CeRh_2Si_2. Although most of unconventional superconductors mediated by spin-fluctuation seem to possess a similar phase diagram, precise properties of conduction electrons are characteristic for each compound.
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