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Thermoelectric properties of CaxCo2O4 aligned crystals

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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.

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Authors and Affiliations

  1. Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, 563-8577, Japan

    M. Shikano & R. Funahashi

  2. Osaka Electro-Communication University, Neyagawa, Osaka, 572-8530, Japan

    M. Kitawaki

Authors
  1. M. Shikano
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  2. R. Funahashi
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  3. M. Kitawaki
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Correspondence to M. Shikano.

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Shikano, M., Funahashi, R. & Kitawaki, M. Thermoelectric properties of CaxCo2O4 aligned crystals. Journal of Materials Research 20, 3082–3087 (2005). https://doi.org/10.1557/JMR.2005.0370

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  • DOI: https://doi.org/10.1557/JMR.2005.0370

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