| Project/Area Number |
63460023
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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 |
KUNII Satoru Tohoku Univ. Department of Physics, Assistant, 理学部, 助手 (10004368)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1990: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1989: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1988: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | Heavy Fermion / Point-contact / dense Kondo / Rare-earth hexaboride / 稀土類ヘキサボライド / 高濃度近藤物質 / ポイントコンタクト・スペクトロスコピー / 希上類ヘキサボライド |
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| Research Abstract |
Point-contact spectroscopy is now becoming a powerful tool for the investigation of the microscopic excitation or the electronic density of states of the bulk-materials.
Following three points were proceeded by the Grant-in-Aid for Scientific Research (B).
1. A point-contact spectrometer for low temperature was completed taking into account the reproducibility and the reliability of the data of point-contact spectroscopy.
2. Various kinds of high quality single crystals of rare earth hexaborides were grown by the floating zone method. Many joint works with other institutions were carried out on these samples.
3. Main results of our point-contact experiments are as follows. (1) It was concluded experimentally that there is a obvious difference between the barrier-type tunneling and the pure metal point-contact. (2) We decided the gap of valence fluctuating compound SmB_6 by the metal point-contact spectroscopy. (3) It was revealed by the point-contact spectroscopy that there should be some characteristic energy which is one order of magnitude larger compared with the Kondo temperature in the dense-Kondo CeB_6 compound. (4) We observed a voltage jump in the current-voltage characteristic of CeB_6 at low temperature under the magnetic field. We are now investigating the correlation of it with the Kondo gap in dense Kondo material.
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