KONDO SEMI-METALLIC STATE OF CeNiSn IN HIGH MAG NETIC FIELDS AT LOW TEMPERATURES

CeNiSn 在低温高磁场中的近藤半金属态

• 批准号: 09640438
• 负责人: SUZUKI Takashi
• 金额: $ 2.3万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640438/
• 关键词: CeNiSn; anomalous metallic state; low carrier system; strongly correlated electron; specific heat; low temperature; high magnetic fields; kondo insulator; 新しい金属; 近籐効果

Thermal and magnetic properties of CeNiSn have been measured on a high-quality single crystals in magnetic fields in order to know the intrinsic ground state of this compound. The specific heat for the purified crystal has been found to remarkably depend on the field along the a axis in contrast with less field dependence for dirty samples.The electronic specific heat divided by temperature C_e_1/T below 2 K stays nearly constant in zero field. With further decreasing temperature, however, C_e_1/T slightly increases below 0.5 K, which suggests that there is a peak structure at the bottom of the pseudo-gap around E_F. The large reduction of C_e_1/T in the field has been found, suggesting that a rigid band picture is no longer realistic below I K.The field dependence indicates that the peak inside the pseudo-gap is collapsed by the external fields. In this study, we concluded that CeNiSn is classified a new-type anomalous metal instead of a Kondo insulator.

为了了解CeNiSn化合物的本征基态，在高质量单晶上测量了磁场中CeNiSn的热性质和磁性质。实验结果表明，纯净晶体的比热对沿a轴沿着方向的场有显著的依赖性，而脏样品的电子比热除以温度C_e_1/T在2K以下在零场下几乎保持恒定。随着温度的进一步降低，C_e_1/T在低于0.5K时略有增加，表明在E_F附近赝能隙底部存在一个峰结构。在磁场中C_e_1/T的大幅度降低表明，在低于1 K时，刚性带的图象不再是现实的。在这项研究中，我们得出结论，CeNiSn被归类为一种新型的反常金属，而不是近藤绝缘体。

项目成果

T.Suzuki et al.: "Acoustic de Haas van Alphen Effect of CeRu_2" Journal of Magnetism and Magnetic Materials. 177-181. 415-416 (1998)

T.Suzuki 等人：“CeRu_2 的声学 de Haas van Alphen 效应”《磁性与磁性材料杂志》。

Y.Janssen et al.: "Giant Magnetoresistance in Ce_2Fe_<17>" Physical Review. B56. 13716-13719 (1997)

Y.Janssen 等人：“Ce_2Fe_<17> 中的巨磁阻”物理评论。

T.Akazawa et al.: "Quadrupolar and Magnetic Phase Diagram of UNiSn" Journal of Physical Society of Japan. 67(9). 3256-3260 (1998)

T.Akazawa 等人：“UNiSn 的四极和磁相图”日本物理学会杂志。

T.Suzuki et al.: "Specific Heat of YbPtSn" Physica. B印刷中. (1999)

T.Suzuki 等人：“YbPtSn 的比热”Physica B（已出版）。

T.Suzuki et al.: "Specific Heat of YbPtSn" Physica B. (in press). (1999)

T.Suzuki 等人：“YbPtSn 的比热”Physica B.（正在印刷中）。