| Project/Area Number |
15206068
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 University |
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Principal Investigator |
MIZUTANI Uichiro Nagoya University, School of Engineering, Professor, 工学研究科, 教授 (00072679)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI Tsunehiro Eco Topia Science Institute, Assistant Professor, エコトピア科学研究機構, 講師 (00293655)
SATO Hirokazu Aichi University of Education, Professor, 教育学部, 教授 (20024094)
NISHINO Yoichi Nagoya Institute of Technology, Faculty of Engineering, Professor, 工学部, 教授 (50198488)
IKUTA Hiroshi Nagoya University, School of Engineering, Associate Professor, 工学研究科, 助教授 (30231129)
BIWA Tetsushi Nagoya University, School of Engineering, Research Associate, 工学研究科, 助手 (50314034)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥45,110,000 (Direct Cost: ¥34,700,000、Indirect Cost: ¥10,410,000)
Fiscal Year 2004: ¥22,880,000 (Direct Cost: ¥17,600,000、Indirect Cost: ¥5,280,000)
Fiscal Year 2003: ¥22,230,000 (Direct Cost: ¥17,100,000、Indirect Cost: ¥5,130,000)
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| Keywords | Hume-Rothery rule / FLAPW / LMTO-ASA / thermoelectric characteristics / quasicrystals and their approximants / Fe2VAl / pseudogap structure / Fermi surface-Brillouin zone interaction / ヒューム・ロザリー則 / 擬ギャップ系 / 熱電変換材料 |
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| Research Abstract |
The present work aimed at exploring physics behind the Hume-Rothery rule by performing the first-principles band calculations and evaluating thermoelectric properties of quasicrystals and their approximants and Fe_2VAl compounds, all being characterized by the possession of the pseudogap at the Fermi level. The main results obtained in this project are listed below.
(1)The electronic structure of the Al-Li-Cu 1/1-cubic approximant has been calculated in the context of the LMTO-ASA method in combination with the NFE model. We proved that the pseudogap is formed as a result of the interaction of electrons at the Fermi level with (631), (543), (710), (550) zone planes.
(2)We have measured the electronic specific heat coefficient, Seebeck coefficient, electrical resistivity and thermal conductivity of the Al-Re-Si,Al-Mn-Si,Al-Pd-Mn-Re-Si and Al-Mn-Re-Si approximants and revealed how the pseudogap structure across the Fermi level determines the thermoelectric characteristics of these pseudoga
… More
p-bearing systems.
(3)We succeeded in swinging a sign of the Seebeck coefficient from a positive to negative value (-140μV/K) by substituting Si for Al and Ti and Mo for V in the Fe_2VAl system, respectively. In the Fe_2VAl, spin fluctuations caused by Fe atoms introduced into the V site are believed to give rise to an enhancement in resistivity, thereby leading to a poor performance of thermoelectric characteristics. To get rid of this difficulty, we synthesized the (Fe-Ru)_2VAl alloys and revealed that a dramatic decrease in magnetization results in a substantial decrease in resistivity and magnetoresistance. This was taken as a proof that the Fe atoms on the V-site contribute to degrade the thermoelectric characteristics of this system.
(4)The FLAPW band calculations have been performed for Cu_5Zn_8,Cu_9Al_4,TM_2Zn_<11>(TM=Ni,Pd,Co,Fe) gamma-brasses. The Fourier spectrum analysis for wave function sustaining the pseudogap at the Fermi level clearly demonstrated that (411), (330) zone are indeed responsible for the formation of the pseudogap to stabilize the unique complex structure at specific electron concentration. Less
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