| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Kenji Tohoku University, Institute for Materials Research, Professor, 金属材料研究所, 教授 (10005861)
MAEZAWA Kunihiko Toyama Prefectural University, Faculty of Engineering, Professor, 工学部, 教授 (90099408)
OMATSUBARA Takemi Tohoku University, Center of Ultra Low Temperature Science, Professor, 極低温科学センター, 教授 (80004331)
ISHIKAWA Masayasu University of Tokyo, Institute for Solid State Physics, Professor, 物性研究所, 教授 (70159705)
SATO Hideyuki Tokyo Metoropolitan University, Faculty of Sciences, Professor, 理学部, 教授 (80106608)
SHIGA Masayuki Kyouto University, Grade School of Engineering, Professor (30026025)
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| Research Abstract |
The materials research team consists of two group ; the one is the crystal growth group which make high-quality single crystals of typical heavy fermion materials showing unusual superconducting behaviors with strong assisotropic nature like UPtィイD23ィエD2, showing meta-magnetic behaviors even in Pauli paramagnetict like CeRuィイD22ィエD2SiィイD22ィエD2 and showing Kondo-semiconducting behaviors like CeNiSn. The second is the serching group of new heavy fermion systems with unusual physical properties.
In the crystal growth group, high-quality single crystal UPtィイD23ィエD2 was grown using tetra-arc furnace followed by solid-state eleclrotranspot purification under ultra-high vacuum condition, the RRR of which reached up to 600. Using this UPtィイD23ィエD2 crystal, the origin of superconducting behaviors was clarifyed. For non-magnetic CeRuィイD22ィエD2SiィイD22ィエD2, the aingle crystal was grown, reaching up to RRR=500. From the measurement of de Haas-van Alphen effect, it was deduced that the sneta-magnetic
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behavior observed in CeRuィイD22ィエD2SiィイD22ィエD2 is originated with the change of electronic states from itenerant f-electron state hybridized with conduction electrons to localized f-electron state. The semimetallic behavior in CeNiSn was clarified by measuring transport properties of high-quality CeNiSn single crystal, which is explainable by the anisotropic energy gap model. By growing the high-quality single crystals of typical heavy fermion materials, our understanding for the physics of heavy fermions have been progressed rapidly and the falling behind of heavy fermion physics in Japan was completely recovered in this research program.
On the other hand, in the new materials searching group, some interesting materials were discovered, but we could not find new unusual heavy fermion supercondutors. The new main materials found in this work are as follows ; There are (1) non-fermi liquid material CeィイD27ィエD2NIiィイD23ィエD2, (2) Kondo-semiconductors CeRhAs and CeィイD23ィエD2SbィイD24ィエD2PtィイD23ィエD2, (3) low dimensional materials CePdAs, CePdSb and CeMgィイD22ィエD2NiィイD29ィエD2, (4) quadrupole ordering material CeィイD23ィエD2PdィイD220ィエD2GeィイD26ィエD2 and UNiSn, (4) non-magnetic heavy fermion materials YbCuィイD25ィエD2 and so on. It sould be noted that these findings made te area of heavy fermion physics more wide in this research program. Less
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