| Project/Area Number |
09450238
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
TAKIZAWA Hirotsugu Dept. Mater. Chem., Tohoku University, Associate Professor, 大学院・工学研究科, 助教授 (90226960)
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| Co-Investigator(Kenkyū-buntansha) |
YAMANE Hisanori Inst. Adv. Mater. Proc., Tohoku University, Associate Professor, 素材工学研究所, 助教授 (20191364)
SHIMADA Masahikio Inst. Adv. Mater. Proc., Tohoku University, Professor, 素材工学研究所, 教授 (80029701)
UHEDA Kyota Dept. Mater. Chem., Tohoku University, Research Associate, 大学院・工学研究科, 助手 (50271862)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 1999: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥8,500,000 (Direct Cost: ¥8,500,000)
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| Keywords | High-pressure synthesis / Antimonides / Transition metal compounds / Phase transition / Ferromagnetism / Skutterudite-type structure / Thermoelectric materials / 圧力誘起相転移 |
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| Research Abstract |
This research put emphasis on the synthesis of novel transition metal compounds under high pressure and temperature condition. Various 3d transition metal - metalloid compounds were newly synthesized in this study. These include transition metal diantimonides, digermanides, and triantimonides. The crystal chemistry of these intermetallic compounds was systematically discussed in terms of chemical bonding scheme and the pressure-induced phase transition.
1. Two types of pressure-induced phase transitions, marcasite- to pararammelsbergite-type and marcasite- to CuAlィイD22ィエD2-type, were found in transition metal diantimonide family. The former occurs in NiSbィイD22ィエD2 and can be explained by effective packing of NiSbィイD26ィエD2 octahedra. The latter was found in CrSbィイD22ィエD2 and the transition accompanied a change in bonding character form mixed ionic and covalent to metallic. High-pressure form of CrSbィイD22ィエD2 showed an itinirant electron ferromagnetic behavior with the Curie temperature of 160 K.
2. Various Group 14 elements could be inserted into the body-centered vacant site of the CoSbィイD23ィエD2 skutterudite host lattice, resulting in the formation of new filled-skutterudite. The incorporated atom showed large thermal vibration amplitude, indicating a possible reduction of thermal conductivity of materials. It was concluded that the atom insertion into the skutterudite host lattice is effective in developing new thermoelectric conversion materials.
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