| Project/Area Number |
09640425
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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 |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Toyama University, Faculty of Science |
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Principal Investigator |
ISIKAWA Yoshikazu Toyama University, Department of Physics, Professor, 理学部, 教授 (20143836)
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| Co-Investigator(Kenkyū-buntansha) |
MAEZAWA Kunihiko Toyama Perfectural University, Faculty of Engineering, Professor, 工学部, 教授 (90099408)
KUWAI Tomohiko Toyama University, Department of Physics, Assistant, 理学部, 助手 (10251878)
MIZUSHIMA Toshio Toyama University, Department of Physics, Assistant, 理学部, 助手 (50135000)
SAKURAI Junji Toyama University, Department of Physics, Professor, 理学部, 教授 (30033814)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | amplitude-modulated magnetic structure / heavy Fermion / de Hass-van Alphen effect / Kondo effect / magnetoresistance / non-localization / compensated metal |
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| Research Abstract |
(1) Studies of de Haas-van Aiphen Effect and Fermi Surfaces of LaNi_2Al_5 :
Magnetoresistance and de Haas-van Alphen measurements have been performed to investigate Fermi-surface property of LaNi_2AI_5, which is a reference material of a magnetic dense-Kondo compound CeNi_2AI_5. Thirteen branches with the frequencies from 1.25x10^6 to 101 x10^6 Oe have been observed in the angular-resolved dHvA measurements, and the magnetoresistance shows the existence of open orbits. The results are well explained by the Fermi surfaces obtainedfrom an FLAPW band-structure calculation.
(2) Studies of de Haas-van Alphen Effect and Fermi Surfaces of Magnetic Dense-Kondo Compound CeNi_2AI_5 :
The experiments of de Haas-van Aiphen (dHvA) effect have been carried out at temperatures down to 40 mK in CeNi_2AI_5 with an incommensurate magnetic structure. A complex phase diagram of the magnetic transition field versus temperature is completed. Many branches of the dHvA frequencies observed in the higher-field regions, II, Ill and IV, have been understood by the branches predicted from the theoretical Fermi surfaces of nonmagnetic reference-sample LaNi_2AI_5 better rather than the theoretical ones in CeNi_2AI_5 with 4f electrons treated as itinerant. Branches observed in the lowest field region I are not clearly analyzed with the theoretical prediction in LaNi_2AI_5 or CeNi_2AI_5, The electrons with heavy cyclotron mass are observed in the region IV ; 12.4 m_0 in eta branch, 11.2 m_0 in zeta branch and 9.6 m_0 in theta branch. Some pairs of parallel branches are observed due to the spin-splitting related to the magnetism, and the exchange energy DELTA E is obtained ; DELTA E=12.9 meV in beta branch and 7.8 meV in delta branch. The relations between the Fermi surfaces and the magnetic structure are discussed.
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