| Project/Area Number |
09640430
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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 | Nagoya Institute of Technology |
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Principal Investigator |
SAKAMOTO Isao Nagoya Institute of Technology, Department of Electrical and Computer engineering, 工学部, 教授 (80094267)
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| Co-Investigator(Kenkyū-buntansha) |
OHARA Shigeo Nagoya Institute of Technology, Department of Electrical and Computer engineering, 工学部, 講師 (60262953)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1999: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Valence fluctuation / Heavy Fermion / De Haas-van Alphen effect / Fermi Surface / Cyclotron Effective Mass / Ytterbium compounds / Uranium Compounds / 4f-Electron / イッテリビウム化合物 / 重い電子系 / 価数揺動系 / f電子 / 強相関電子系 / 強相関系 / 重り電子系 |
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| Research Abstract |
Valence fluctuation and heavy Fermion phenomena are observed in ytterbium and uranium compounds that have the nearest neighbor distance d_<R-R> between rare-earth ions smaller than some critical value, nearly equal to 0.45nm. The decrease in d_<R-R> is expected to increase hybridization between conduction electrons and 4-f electrons of rare-earth ions. In the present work we have measured the de Haas-van Alphen effect of YbZn_<11> (d_<R-R>=0.569nm), YbSn_3 (d_<R-R>=0.468nm), YbBi_2 (d_<R-R>=0.420nm), YbAl3 (d_<R-R>=0.420nm) and UGa_2 (d_<R-R>=0.400nm) to investigate the dependence of the Fermi surface properties on the hybridization between conduction and 4-f electrons The results for YbSn_3 show that the dHvA frequencies range from 60T to 3000T and the cyclotron masses from 0.13m_0 to 0.44m_0, where m_0 is the free electron mass. For YbZn_<11> the dHvA frequencies range from 200T to 11000T and the cyclotron masses are nearly the same as those of YbSn_3. These results indicate that YbS
… More
n_3 is a compensated metal and Yb ions in YbSn_3 and YbZn_<11> are divalent. The dHvA frequencies of UGa_2 range from 20T to 1300T.The observed cyclotron masses range from 0.3m_0 to 3.3m_0. They are larger than those of YbSn_3 and YbZn_<11> by a factor of ten. Field dependence of
the dHvA frequency is observed in the lowest frequency oscillations in UGa_2. These results indicate that the 5f electrons in UGa_2 hybridize appreciably with the conduction electrons. We have also measured the de Haas-van Alphen effect in LuAl3, which is a reference material for YbAl3. Observed frequencies range from 400 T to 23 kT.The observed cyclotron effective masses range from 0.3m0 to 1m0. A band structure calculation was carried out by a full potential linearized APW method. The gross feature of the observed results was explained by the calculation. The measurement of YbAl3 has not been observed at 0.3K in magnetic fields as high as 15T.We will try to measure the dHvA effect of YbAl_3 in lower temperatures using dilution refrigerator. Less
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