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Thermoelectric Properties of CaxCo2O4 Aligned Crystals

Published online by Cambridge University Press:  03 March 2011

M. Shikano ,
R. Funahashi  and
M. Kitawaki
M. Shikano
Affiliation:
Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
R. Funahashi
Affiliation:
Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka 563-8577, Japan
M. Kitawaki
Affiliation:
Osaka Electro-Communication University, Neyagawa, Osaka 572-8530, Japan
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Abstract

Agglomerates of aligned crystals of CaxCo2O4 with a layer of CoO2 were grown using a chloride flux technique, and their thermoelectric properties in air were determined. The agglomerates take the form of a very thin flakelike cluster of crystals with a typical size of almost 3 × 2 × 0.07 mm. The values of thermoelectric power along the ab-plane are larger than 200 μV K−1 at temperatures above 873 K and reach almost 300 μV K−1 at 973 K. The temperature dependence of the electrical resistivity along the ab-plane shows bends around 450 and 825 K, and the ln ρab−T−1 curve followed an Arrhenius-type behavior below 450 K. Temperature dependence of thermal conductivity indicated that stacking faults along the c axis induce phonon scattering like that in a misfit-layered structure. The effect of the CoO2 layer on thermoelectric performance is discussed in comparison with related compounds.

Keywords

Flux growthThermoelectricityTransmission electron microscopy (TEM)
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 11 , November 2005 , pp. 3082 - 3087
Copyright
Copyright © Materials Research Society 2005

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