| Project/Area Number |
07640512
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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 |
物性一般(含基礎論)
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
YAMADA Kousaku Kyoto University, Physics, Professor, 大学院・理学研究科, 教授 (90013515)
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| Project Period (FY) |
1995 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1996: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | Ferromagnetism / Transition metals / Hund's coupling / Orbital degeneracy / 金属強磁性 / 鉄族 / 電子相関 / ニッケル / 鉄 / コバルト / グッツヴィラ-近似 |
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| Research Abstract |
The mechanism of the itinerant ferromagnetism realized in Fe, Co and Ni has been investigated by using Gutzwiller approximation. Through the investigation, the role of orbital degeneracy and Hund's coupling has been made clear in realizing the ferromagnetism. In addition to this study, excitation spectra such as the spin waves and the Stoner excitations have been calculated to make clear the conditions in which the ferromagnetic ground states are stable. We have also explained the difference between Fe, Co and Ni, incomplete and complete ferromagnetism, on the basis of the difference of their density of states.
Moreover, we have made clear the roles of the Hund's coupling in the Kondo effect. The roles of magnetism in the heavy fermions and the high temperature superconductivity have been studied. We can explain the superconductivity on the basis of the antiferromagnetic spin fluctuation.
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