1992 Fiscal Year Final Research Report Summary
The Study for Heavy Fermion State in f- electron pnictides
| Project/Area Number |
03452027
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
OCHIAI Akira 東北大学, 金属材料研究所, 助手 (90183772)
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| Project Period (FY) |
1991 – 1992
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| Keywords | f-electron / Pnictides / Heavy Fermion / Low carrier / Kondo State / de Haas effect / High Pressure / High Magnetic Field |
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| Research Abstract |
We could make remarkable development for the extensive fundarmental properties of Ce monopnictides under ultra high pressure; The transport properties and the change of the Fermi surfaces area under high pressure have been measured. The Fermi surfaces area of the reference system of LaSb increased with increasing pressure as in the usual case. However that of CeAs decreased with increasing pressure. The latter case is clearly due to f electron effect and bring the interesting problem to be solve The neutron diffraction and scattering revealed the variation of complicated magnetic structure and crystalline field splitting with increasing pressure. The magnetization for CeP single crystal have been measured up to 60T and showed nearly 10 step magnetization at the magnetic field just same time for Landau level crossing of the hole Fermi sphere and attracted many interest for this new phenomena. The discovering of largest fermi surface in CeSb by accoustic dHvA effect proved the rightness of the p-f mixing theory. The success of very pured single crystal of LaAs can bring us to new stage ofd extremly low carrier system of 10-4 order of carrier number and expect to clearfy the behavior of the quantum limit of Landau motion for avaiable high magnetic field. The dHvA measurement for the most typical heavy Fermion state of low carrier system of YbAs and could detect the electron and one hole Fermi surface with effective mass below 1 and were not consistent with large coefficient of the electronic specific heat capacity. It should be another hole Fermi surface with very large mass up to several thousand. This large massenhancement is particular point of low carrier system and not seen in usual mettallic heavy Fermion systems. The most impressive discovery in this project is the heavy Fermion state of insulating state in Sm3X4 and suggest the fundermental revolution of usual heavy Fermion concept.
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