2007 Fiscal Year Final Research Report Summary
Pseudogap Formation and Thermoelectric Properties of Heusler-type Compounds
| Project/Area Number |
17360311
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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 |
Physical properties of metals
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
NISHINO Yoichi Nagoya Institute of Technology, Dpt of MateialsScieice ardEngineaing, Professor (50198488)
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| Co-Investigator(Kenkyū-buntansha) |
SODA Kazuo Nagoya University, Dpt of Qranlum Engineering, Professor (70154705)
IDE Naoki Nagoya University, Dpt of Mateials Sciece and Engineering, Assistant Professor (60262945)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Heusler compounds / Pseudogap / Thermoelectric Materials / Seebeck effect / Electrical conductivity / Thermal conductivity / Site oreference / Electron concentration effect |
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| Research Abstract |
The thermoelectric power of Fe_2VA1 can be expected to be well enhanced by doping or off-stoichiometry, because the density of states rises sharply in both sides of the pseudogap. We have investigated the temperature dependence of the Seebeck coefficient and the electrical resistivity in the Fe_2VAI-based alloys, in addition to the measurement of the thermal conductivity at room temperature, to clarify the doping effect on the thermal and transport properties. The compositional variation of the Seebeck coefficient falls on a universal curve, irrespective of the doping elements, when plotted against the valence electron concentration (VEC), instead of the composition of the doping elements. The net effect of doping is most likely to cause an appreciable shift of the Fermi level from the central region in the pseudogap without modifying the band structure in any essential manner. The substitution of heavy atoms certainly acts in favor of the development of thermoelectric materials because of a substantial reduction of the lattice thermal conductivity. Co-doping of heavier atoms is also effective to reduce the lattice thermal conductivity while retaining the low electrical resistivity as well as the large Seebeck coefficient. For the Heusler compound Fe_<2-x>Co_xTiAl with VEC=6, the compositional variation of the Seebeck coefficient is in line with a pseudogap scenario where the off-stoichiometry causes a rigid-band-like shift of the Fermi level from the central region in the pseudogap. The low Seebeck coefficient may be attributed to an atomic disorder between Fe and Co
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Research Products
(87 results)
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[Journal Article] High-Resolution Soft X-Ray Photoelectron Study of Density of States and Thermoelectric Properties of the Heusler-type Alloys(Fe_<2/3>V_<1/3>)_<100-y>Al_y2005
Author(s)
K. Soda, H. Murayama, K. Shimba, S. Yagi, T. Takeuchi, U. Mizutani, H. Sumi, M. Kato, H. Kato, Y. Nishino, 他4名
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Journal Title
Physical Review B 71
Pages: 245112/1-6
Description
「研究成果報告書概要(和文)」より
Peer Reviewed
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[Presentation] ホイスラー型FeCoTiAlの電子構造2007
Author(s)
宮崎秀俊, 曽田一雄, 八木伸也, 加藤政彦, 岩瀬啓吾, 西野洋一
Organizer
日本金属学会2007年春期(第140回)講演大会(シンポジウム)
Place of Presentation
千葉
Year and Date
20070327-29
Description
「研究成果報告書概要(和文)」より
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[Presentation] 3p-3d Resonance Photoemission Spectroscopy of Heusler-type Fe2VA1_<1-z>Si_z2006
Author(s)
H. Miyazaki, M. Inukai, S. Otra, T. Suzuki, K. Soda, S. Yagi, M. Kato, Y. Nishino, T. Ito, S. Kimura
Organizer
The Physical Society of Japan, 2006 Annual Meeting
Place of Presentation
Matsuyama
Year and Date
20060327-30
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Fe基ホイスラー型合金の電子構造2006
Author(s)
曽田一雄, 宮崎秀俊, 八木伸也, 加藤政彦, 西野洋一
Organizer
日本金属学会2006年春期(第138回)講演大会(シンポジウム)
Place of Presentation
東京
Year and Date
20060321-23
Description
「研究成果報告書概要(和文)」より
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