Study of Anomalous Metal-Insulator Transition of Filled Skutterudite-Type Compounds

填充方钴矿型化合物的反常金属-绝缘体转变研究

• 批准号: 14540318
• 负责人: SEKINE Chihiro
• 金额: $ 2.5万
• 依托单位: MURORAN INSTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540318/
• 关键词: Skutterudite; Metal-insulator transition; Nesting; Quadrupole transition; Structural phase transition; Antiferromagnetism; 金属リン化物; 希土類化合物; 強相関電子系

PrRu_4P_<12> and SmRu_4P_<12> crystallized in the cubic filled skutterudite structure (space group Im-3) undergo a metal-insulator (M-I) transition at T_<MI>=62K and 16K, respectively. For PrRu_4P_<12>, various experiments suggest that the M-I transition is non-magnetic one of second order. To clarify the mechanism of the M-I transition, we have studied the crystal structure below T_<MI> using electron and synchrotron radiation X-ray diffraction. The superlattice spots were observed below T_<MI>. It is suggested that the space group of low temperature phase is Pm-3 For SmRu_4P_<12>. magnetic susceptibility clearly shows an anomaly at T_<MI> in contrast to PrRu_4P_<12>. We have measured in detail the specific heat, electrical resistivity and magnetization under high magnetic field. The detailed measurements have revealed that the M-I transition occuers in two successive steps. The field dependence up to 30T of the two anomalies suggests that the two successive transitions are antiferro-quadrupolar ordering and antiferro-magnetic order.

立方填充方钴矿结构（空间群Im-3）中结晶的PrRu_4P_<12>和SmRu_4P_<12>分别在T_<MI>=62K和16K时经历金属-绝缘体（M-I）转变。对于PrRu_4P_<12>，各种实验表明M-I转变是二阶非磁性转变。为了阐明M-I跃迁的机理，我们利用电子和同步辐射X射线衍射研究了T_<MI>以下的晶体结构。在T_<MI>以下观察到超晶格斑点。建议低温相空间群为Pm-3 For SmRu_4P_<12>。与 PrRu_4P_<12> 相比，磁化率清楚地显示出 T_<MI> 处的异常。我们详细测量了强磁场下的比热、电阻率和磁化强度。详细的测量表明，M-I 转变发生在两个连续的步骤中。两个异常的场依赖性高达 30T，表明这两个连续跃迁是反铁四极有序和反铁磁有序。

项目成果

M.Matsunami: "Infrared study on the metal-insulator transition in filled skutterudites RRu_4P_<12> (R=Pr, Sm)"J.Magn.Magn.Mater.. (2004)

M.Matsunami：“填充方钴矿 RRu_4P_<12> (R=Pr, Sm) 中金属-绝缘体转变的红外研究”J.Magn.Magn.Mater.. (2004)

C Sekine: "Magnetic phase diagram of filled skutterudite compound SmRu_4P_<12>"Acta Physica Polonica B. 34. 983-986 (2003)

C Sekine：“填充方钴矿化合物SmRu_4P_<12>的磁相图”Acta Physica Polonica B.34.983-986(2003)

L.Hao: "Crystal-lattice modulation of the metal-insulator transition system PrRu_4P_<12>"J.Magn.Magn.Mater.. (2004)

L.Hao：“金属-绝缘体过渡体系PrRu_4P_<12>的晶格调制”J.Magn.Magn.Mater.. (2004)

C.H.Lee: "A study of the crystal structure at low temperature in the metal-insulator transition compound PrRu_4P_<12>"J.Magn.Magn.Mater.. (2004)

C.H.Lee：“金属-绝缘体过渡化合物 PrRu_4P_<12> 低温晶体结构的研究”J.Magn.Magn.Mater.. (2004)

R.Giri: "Magnetic Properties of Sm-Based Filled Skutterudite Phosphides"Physica B. 329-333. 458-459 (2003)

R.Giri：“Sm 基填充方钴矿磷化物的磁性”Physica B. 329-333。