| Project/Area Number |
08404023
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TAKABATAKE Toshiro Grad.School of ADSM,HIROSHIMA UNIVERSITY Prof., 大学院・先端物質科学研究科, 教授 (40171540)
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| Co-Investigator(Kenkyū-buntansha) |
UMEO K Grad.School of ADSM,Res.Assoc., 大学院・先端物質科学研究科, 助手 (10223596)
EKINO T Fac.Integr.Arts & Sci., Assoc.Prof., 総合化学部, 助教授 (40185103)
SUZUKI T Grad.School of ADSM,Assoc.Prof., 大学院・先端物質科学研究科, 助教授 (00192617)
IGA F Grad.School of ADSM,Assoc.Prof., 大学院・先端物質科学研究科, 助教授 (60192473)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥40,800,000 (Direct Cost: ¥40,800,000)
Fiscal Year 1998: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1997: ¥15,000,000 (Direct Cost: ¥15,000,000)
Fiscal Year 1996: ¥24,400,000 (Direct Cost: ¥24,400,000)
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| Keywords | Kondo Semiconductor / Energy Gap / Hybridization / Electron Tunneling / Single Crystal / Low-Carrier Density System / 強磁場 / 高圧 / 磁気抵抗 / メタ磁性 / 光電子分光 / 低温高圧 / 凝ギャップ / 電気抵抗 / 極低温比熱 |
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| Research Abstract |
We have studied the gap formation in the Kondo-lattice systems YbB12, Ce3Bi4Pt3, CeNiSn and CeRhSb by means of high-quality single crystals. New findings are as followings.
1. Anisotropic Gap : Tunnel spectroscopy revealed the B SC-type gap in YbBI2 and Ce3Bi4Pt3. Substitution of Lu for Yb in YbB12 gives rise to a midgap state with keeping the gap width unchanged. By contrast, the gap in CeNiSn and CeRhSb is anisotropic with a residual density of states. Only 1% substitution in CeNiSn leads to a unitarity scattering of the residual carriers. The gap anisotropy is much weakened in CeRhSb due to the strong hybridization.
2. Ground state of CeNiSn : It is a semimetallic state with an extremely low carrier density. A sort of magnetic polaron is indicated by the anomalous field dependence of the magnetoresistance and specific heat below 0.5 K.
3. Effect of high magnetic field : The gap in CeNiSn is closed by application of field of 14 TAU along the a axis. However, a higher field of 30 T is required to close the gap in CeRhSb. For YbB12, a first order transition from a semiconductor to a metal is found near 50 TAU The sharp peaks in the magnetoresistance indicate the presence of fine structure in the gap.
4. Effect of pressure : CeNiSn exhibits a pressure-induced magnetism, which is the first example among the Ce-based compounds.
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