1990 Fiscal Year Final Research Report Summary
Ultrasonic Investigation of f-Electron Systems
| Project/Area Number |
01460027
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Tohoku University |
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Principal Investigator |
GOTO Terutaka Research Institute for Scientific Measurements, Tohoku University, Associate Prof., 科学計測研究所, 助教授 (60134053)
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| Co-Investigator(Kenkyū-buntansha) |
SAKATSUME Shinich Cryogenic Center, Tohoku University, Researcher, 低温センター, 助手 (20005896)
SUZUKI Takashi Department of phys, Tohoku University, Assodiate Prof,, 理学部, 助教授 (30004344)
KOMATSUBARA Takemi Department of Phys, Tohoku University Prof., 理学部, 教授 (80004331)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Ultrasonic / f-electron / Heavy electron / Valence Fluctuation / de Haas-van Alphen Effect / Rare earth compound |
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| Research Abstract |
Ultrasonic measurements have been employed for the investigation of the elastic properties of the various rare earth compounds involving the strongly correlated 4f-electrons. The ultrasonic apparatus based on the phase comparison method, which has been developed by our group, reveals the extremely high resolution to detect the sound velocity change better than 10^<-7>. In the present research project, the many improvements for the high frequency sound wave experiments up to 1.3GHz have been performed. The Signal generator, 9087, Racal-Dana, England, plays an important role. For the generation of the high frequency sound waves, we developed the fabrication technique of the piezoelectric film of ZnO and PVDF (polyvinylidene-fluoride). In the last two years, the new apparatuses for the low temperature ultrasonic experiments have been established. The ^3He cryostat of the continuouscirculation provided the experiments at 0.32K. The ^3He-^4He dilution refrigerator is now cooled down to 8mK.
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It Should be noted that the 3He cryostat and the dilution refrigerator were developed by the machine shop in Research Institute for Scientific Measurements of Tohoku University.
The characteristic features of the heavy electron and valence fluctuation states in rare earth compounds have been investigated by the ultrasonic measurements. It should be emphasized that the energy gap states in SmB_6 and CeNiSn were detected by the ultrasonic probes. The acoustic de Haas-van ALphen effect was also important subject of the present project. The measurements of the quantum oscillation of sound wave velocity on YCu_2,CeCu_2, UB_<12>, LaSb, CeSb, LaSn_3, CeSn_3 have been performed. The successful observation of acoustic of dHvA effect of the heavy electron compound CeB_6 utilizing the dilution refrigerator was a very important progress in the present project. The systematic investigation of the heavy electron systems with ultrasonic method at very low temperatures in still interesting and important subject. Less
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Research Products
(10 results)
