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Enhanced Thermoelectric Properties of [Ca2CoO3-δ]0.62CoO2 Polycrystalline Bulk by Control of Microstructure and Oxygen Content

Published online by Cambridge University Press:  11 February 2011

M. Sano ,
S. Horii ,
I. Matsubara ,
R. Funahashi ,
M. Shikano ,
K. Otzschi ,
J. Shimoyama  and
K. Kishio
M. Sano
Affiliation:
Department of Superconductivity, University of Tokyo, Tokyo 113–8656, Japan
S. Horii
Affiliation:
Department of Superconductivity, University of Tokyo, Tokyo 113–8656, Japan
I. Matsubara
Affiliation:
National Institute of Advanced Industrial Science and Technology, Osaka 563–8577, Japan
R. Funahashi
Affiliation:
National Institute of Advanced Industrial Science and Technology, Osaka 563–8577, Japan
M. Shikano
Affiliation:
National Institute of Advanced Industrial Science and Technology, Osaka 563–8577, Japan
K. Otzschi
Affiliation:
Department of Superconductivity, University of Tokyo, Tokyo 113–8656, Japan
J. Shimoyama
Affiliation:
Department of Superconductivity, University of Tokyo, Tokyo 113–8656, Japan PRESTO/JST, Japan
K. Kishio
Affiliation:
Department of Superconductivity, University of Tokyo, Tokyo 113–8656, Japan
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Abstract

We report preparation of highly grain-aligned and densified [Ca2CoO3-δ]0.62CoO2 bulks and a change of thermoelectric performance for their bulks with different oxygen deficiencies (dgrl). The highly c-axis aligned and highly densified samples which showed low electronic resistivities at room temperature, were obtained by combination of magnetic alignment and spark plasma sintering methods. Electronic resistivity p and Seebeck coefficient S along the ab plane were systematically changed with oxygen contents and a power factor was consequently enhanced up to 3.5×10--6 Wcm-1K-2 at 300K for the sample annealed at 500°C in air. Moreover, the magnetic properties also showed a systematic change with oxygen contents.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 755: Symposium DD – Solid-State Chemistry of Inorganic Materials IV , 2002 , DD10.4
Copyright
Copyright © Materials Research Society 2003

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References

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