1995 Fiscal Year Final Research Report Summary
De Haas-van Alphen Effect in Rare-Earth Gallium compounds.
| Project/Area Number |
06640473
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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 |
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 Engineering, Associate Professor, 工学部, 助教授 (80094267)
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| Co-Investigator(Kenkyū-buntansha) |
OHARA Shigeo Nagoya Institute of Technology, Department of Engineering, Assistant, 工学部, 助手 (60262953)
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| Project Period (FY) |
1994 – 1995
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| Keywords | de Haas-van Alphen effect / Fermi Surface / Rare-earth compounds / Brillouin zone / 4-f electrons / itinerant and localized electrons |
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| Research Abstract |
We have improved the apparatus for measuring de Haas van Alphen (dHvA) effect to obtain the dHvA Signal at temperature as low as 0.3K in magnetic fields of 12T with the aid of Grant-in-Aid of Scientific Research. Using this system we have measured the HvA effect of the rare-earth (RE) gallium compounds of PrGa2, SmGa, GdGa2 and LaGa2. The LaGa2 is known as the reference material of REGa2 compounds. The measurements of dHvA effects were also made on the ytterbium compounds YbSn3 and YbZn11 and the uranium compound UGa2. the gross features of the results are as follows : (1) The angular dependences of dHvA frequencies of PrGa2 and GdGa2 are very similar to that of LaGa2. There are however some branches in them that are not corresponding to that of LaGa2. This shows that the magnetic Brillouin zones formed in antiferromagnetic states of PrGa2 and GdGa2 affect the band structures of these compounds and create the new Fermi surfaces in these compounds. (2) The results in SmGa2 are very different to that of LaGa2 : the multiple connection of Fermi surface in the [001] direction observed in LaGa2 is completely broken. This indicates that 4f2+level just above the Fermi level mixes with the s, p and d bands and the valence of Sm ion is partly fluctuated between 2+ and 3+. (3) The origin of the modulated magnetic structure incommensurate with the lattice observed in PrGa2 and CeGa2 is found to be due to the nesting effect of the Fermi surface. The wave numbers of the modulated magnetic structures agree with the nesting vector of the nesting effect.
We continue to investigate the dHvA effect of other RE compounds as well as uranium compound to understand the effect of 4f and 5f electrons on magnetic and heavy electron properties.
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