1997 Fiscal Year Final Research Report Summary
Coherence and Spin correlations in Kondo Semiconductors
| Project/Area Number |
08044091
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TAKABATAKE Toshiro HIROSHIMA UNIVERSITY Fac.Science, Professor, 理学部, 教授 (40171540)
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| Co-Investigator(Kenkyū-buntansha) |
KALVIUS Geor ミュンヘン工科大学, 物理学科, 教授
REGNAULT Lou グルノーブル原子力研究所, 主任研究員
KADOWAKI Hiroaki Fac.Sci.Tokyo Metr.Univ., Assoc.Prof., 理学部, 助教授 (70194876)
UMENO Kazunori HIROSHIMA UNIVERSITY Fac.Science, Reser.Assoc., 理学部, 助手 (10223596)
IGA Fumitoshi HIROSHIMA UNIVERSITY Fac.Science, Assoc.Prof., 理学部, 助教授 (60192473)
REGNAULT Louis-Pierre CEA,DRF,Grenobole, Group leader
KALVIUS Georg Michael Phys.Dep.T.U.Munchen, Prof.
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| Project Period (FY) |
1996 – 1997
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| Keywords | Kondo semiconductor / Neutron scattering / Muon spin relaxation / Spin density wave / Spin gap / Non-Fermi liquid behavior |
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| Research Abstract |
The coherence and spin correlations in Kondo semiconductors have been studied by neutron scattering, muSR and low-temperature magnetic measurements on single crystals of CeNiSn, Ce7Ni3 and YbB12 grown at Hiroshima University.
1.Neutron scattering study
(1) The spin excitaion in CeNiSn was studied in magnetic fields up to 12 T.The field dependence of the peak at an energy of 4 meV traces that of the specific heat. This quasi-one dimensional correlation is found to be essential for gap formation in CeNiSn.
(2) The inelastic scattering from Ce7Ni3 near the critical pressure of 4 kbar can be described by a universal function of omega/T.
(3) The intensity of spin excitaion of YbB12 at 14 meV shows strong q dependence with a sharp maximum at (111).
2.Muon spin relaxation study
(I) CeNil-xCuxSn exhibits a nonmagnetic-magnetic transition near x=0.06.
(2) The muSR results on Ce7Ni3 indicates the first-order SDW transition at 1.8K and second-order transition at 0.7K.The direction of the magnetic moment of Ce ions tilts from the c axis.
3.Low-temperature study of quantum critical behavior
(I) Both the specific heat divided by temperature and magnetic susceptibility of CeNi0.95Cu0.05Sn continue to increase down to 0.025K.
(2) Non-Fermi liquid behavior in the specific heat of Ce7Ni3 observed above 0.5K under a pressure of 0.4 GPa is found to be a crossover to the Fermi liquid behavior below 0.2K.
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