| Project/Area Number |
60540228
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物性一般（含極低温･固体物性に対する理論）
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
AYAO OKIJI FACULTY OF ENGINEERING, OSAKA UNIVERSITY PROFESSOR, 工学部, 教授 (20029002)
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| Co-Investigator(Kenkyū-buntansha) |
NORIO KAWAKAMI FACULTY OF ENGINEERING, OSAKA UNIVERSITY ASSISTANT, 工学部, 助手 (10169683)
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| Project Period (FY) |
1985 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1987: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Rare-Earth Compounds / Heavy Fermion / Valence Fluctuation / セリウム / 近藤効果 |
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| Research Abstract |
This research is aimed at the theoretical investigation of the properties characteristic of the Ce(Yb) alloy systems. The systematic study is based on the exact solution of the Kondo model and its application to the transport and dynamical quantities. The main results obtained in the present investigation are summarized as follows.
1) Static properties: We calculate the temperature-dependent specific heat and successfully explain the anomalous behaviour of specific heat observed for CeAL_3 and CECu_2Si_2. The magnetization curves are also calculated for these two compounds at low temperatures. The obtained results are quantitatively in good agreement with the experimental findings.
2) Dynamical properties: The low-frequency dynamical susceptibility is calculated exactly for the Ce-Kondo system in the crystalline field. The obtained results are used to explain the large anisotropy observed for the nuclear magnetic relaxation of CeRu_2Si_2. The recent experiment of the polarized neutron scattering for CeCu_2Si_2 is investigated as well.
3) Transport properties: The transport coefficients such as magnetoresistance and the thermopower are calculated exactly for the dilute Ce-Kondo system at low temperatures. As for the concentrated system the single site approximation is used to take account of the coherence effect due to the periodicity. The positive magnetoresistance observed for CeAl_3 and CuCu_6 can be explained by the present calculation. The anomalous behaviours of the thermal conductivity and the Lorentz number are investigated as well.
4) Summary: Many characteristic properties of Ce(Yb) compounds are found to be explained with the use of the exact solution of the Kondo model. As fo the transport phenomena of the concentrated system, however, it is necessary to take account of the coherence effect more microscopically, which remains the main problem in the future work.
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