2003 Fiscal Year Final Research Report Summary
Study of Anomalous Metal-Insulator Transition of Filled Skutterudite-Type Compounds
| Project/Area Number |
14540318
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | MURORAN INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
SEKINE Chihiro MURORAN INSTITUTE OF TECHNOLOGY, Department of Electrical and Electronic Engineering, Associate Professor, 工学部, 助教授 (60261385)
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| Co-Investigator(Kenkyū-buntansha) |
LEE Chul-ho MURORAN INSTITUTE OF TECHNOLOGY, (AIST), 電力エネルギー研究部門, 研究員 (80358358)
SHIROTANI Ichimin MURORAN INSTITUTE OF TECHNOLOGY, Department of Electrical and Electronic Engineering, Professor, 工学部, 教授 (90110692)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Skutterudite / Metal-insulator transition / Nesting / Quadrupole transition / Structural phase transition / Antiferromagnetism |
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| Research Abstract |
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.
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