2005 Fiscal Year Final Research Report Summary
The study in thermoelectric oxide thin films for practical use at room temperature
| Project/Area Number |
16360479
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Energy engineering
|
|---|
| Research Institution | Nagoya University |
|---|
Principal Investigator |
YOSHIDA Yutaka Nagoya University, Graduate school of engineering, Associate Professor, 工学研究科, 助教授 (20314049)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKAI Yoshiaki Nagoya University, Graduate school of engineering, Professor, 工学研究科, 教授 (50109287)
|
|---|
| Project Period (FY) |
2004 – 2005
|
| Keywords | thermoelectric materials / oxide materials / thin film / microstructure |
|---|
| Research Abstract |
In order to adapt thermoelectric material to practical use in the future, oxide materials of which the thermoelectric properties do not deteriorate in the high temperature atmosphere are expected. Although the p-type oxide materials which show the figure of merit of ZT=1 around 1000 K are reported, there are few oxide materials which show the excellent thermoelectric properties in the middle temperature range (300-800 K). Therefore we studied RE_2CuO_4(RECO) as the high-performance oxide thermoelectric materials in the middle temperature range. It is well known that carrier doped RE_<2-x>M_XCuO_4(REMCO) becomes a superconductor. In this study, we prepared Sm_<2-x>Ce_XCuO_4(SCCO) as the n-type film and La_<2-x>M_XCuO_4(LMCO:M=Ca,Sr,Ba) as p-type one, and evaluated the thermoelectric properties. REMCO thin films (x=0.01-0.15) were deposited on MgO (100) and SrTiO_3 (100) substrate by the pulsed laser deposition (PLD) method.
SCCO thin films were confirmed that c-axis was parallel to the s
… More
ubstrate normal and in-plane alignment was cube-on-cube for the substrate. The Seebeck coefficient and electrical resitivity decreased with the increasing an amount of Ce^<4+> substitution. And the electrical resitivity showed the metallic temperature dependences. We calculated the power factor from those values and found that the highest value of 1.14 mW/mK^2 at 323 K was achieved by SCCO thin film with x=0.02. This value is about ten times higher than that in Nd_<1.95>Ce_<0.05>CuO_4 bulk at 320 K.
Furthermore, we studied about the thermoelectric mechanisms and properties of mixed crystal RE_<2-x>Ce_XCuO_4(RE=Gd,Sm,Pr) thin film. Electric resitivity and carrier concentration of the mixed crystal RE_<2-x>Ce_XCuO_4 thin film was due to the ion size of the RE element and oxygen deficiencies at the regular sites.
High power factor values in low temperature demonstrate the potential of RECO system for the thermoelectric device. In the future we will study thermoelectric properties and microstructure of RECO and mixed crystal RECO film doped with artificial defects. Less
|
