Thermoelectric Properties of the Layered Cobaltite Ca<SUB>3</SUB>Co<SUB>4</SUB>O<SUB>9</SUB> Epitaxial Films Fabricated by Topotactic Ion-Exchange Method
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To clarify the thermoelectric properties of the layered cobalt oxide Ca<SUB>3</SUB>Co<SUB>4</SUB>O<SUB>9</SUB> epitaxial film fabricated by the topotactic ion-exchange method [K. Sugiura <I>et al.</I>, Appl. Phys. Lett. <B>89</B>, 032111 (2006)], the electrical resistivity (ρ), Hall coefficient (R<SUB>H</SUB>), and Seebeck coefficient (<I>S</I>) of high quality Ca<SUB>3</SUB>Co<SUB>4</SUB>O<SUB>9</SUB> epitaxial film were examined over the temperature range 10–1000 K. The film exhibited a low ρ of 4.0×10<SUP>−3</SUP> Ω cm and a large <I>S</I> of ∼+200 μV K<SUP>−1</SUP>, which leads to the thermoelectric power factor of 1.0×10<SUP>−3</SUP> W m<SUP>−1</SUP> K<SUP>−2</SUP>, at 1000 K. Furthermore, the film exhibited good thermal stability at 1000 K in air.
- MATERIALS TRANSACTIONS
MATERIALS TRANSACTIONS 48(8), 2104-2107, 2007
The Japan Institute of Metals and Materials