| Project/Area Number |
21560687
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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 |
Physical properties of metals
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| Research Institution | Nagasaki University |
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Principal Investigator |
MORIMURA Takao 長崎大学, 大学院・工学研究科, 助教 (30230147)
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| Co-Investigator(Kenkyū-buntansha) |
HASAKA Masayuki 長崎大学, 大学院・工学研究科, 教授 (30039698)
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| Project Period (FY) |
2009 – 2011
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| Project Status |
Completed (Fiscal Year 2011)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2011: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2010: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2009: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | 原子・電子構造 / 透過型電子顕微鏡 / 熱電変換材料 / ゼーベック係数 / 無次元性能指数 / 走査型透過電子顕微鏡 / ALCHEMI / 熱伝導度 / 電気伝導度 / STEM |
|---|
| Research Abstract |
It is well known that Ca_3Co_4O_9 is a good thermoelectric material and addition of dopants is an effective way to improve its properties. To gain insight on the role of Sr-doping, we used scanning transmission electron microscopy(STEM), energy-dispersive X-ray spectroscopy(EDX), and electron energy loss spectroscopy(EELS). STEM images and EDX analyses indicated that Sr substitutes in the rocksalt layer. It is estimated from the EELS results that the Co valence values are(3. 48±0. 10)+ in the rocksalt layer and(3. 02±0. 08)+ in the CoO_2 layer, respectively, which are similar to the non-doped Ca_3Co_4O_9 case. It is inferred from these results that Sr-doping effectively enhances the figure of merit by decreasing the thermal conductivity in the rocksalt layer, whereas it does not significantly alter the electrical properties.
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