Synthesis and thermoelectric characterization of polycrystalline Ni1−xCa x Co2O4 (x=0–0.05) spinel materials

  • Yoshinobu Fujishiro
  • Kouich Hamamoto
  • Osamu Shiono
  • Shingo Katayama
  • Masanobu Awano


Ca doped NiCo2O4 spinel materials were synthesized by conventional solid state reactions at 900 °C. Thermoelectric properties of polycrystalline products were characterized at high temperature range of ∼800 °C in air. d.c. conductivity of the prepared polycrystalline 5 mol % Ca doped NiCo2O4 was about 60 S m−1 at 300 °C. The value of d.c. conductivity was increased with the temperature increasing. Thermoelectric voltage of polycrystalline Ni1−xCa x Co2O4 (x=0–0.05) was positive at 300–800 °C, this showed p-type thermoelectric properties. The Seebeck coefficient of 5 mol % Ca doped NiCo2O4 was ca. 300 μV/K at 600 °C. The value of the Seebeck coefficient of Ni1−xCa x Co2O4 polycrystalline products decreased with the increasing temperature. Thermal conductivity of 5 mol % Ca doped NiCo2O4 was ca. 2.2 W m−1 K−1 at 600 °C. The estimated thermoelectric figure-of-merit, Z, of 5 mol % Ca doped NiCo2O4 spinel polycrystalline product was about 3.5×10−5 K−1 at 600 °C.


Thermal Conductivity Solid State Electronic Material Solid State Reaction Thermoelectric Property 
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  1. 1.
    I. Bredikhin, K. Maeda and M. Awano, J. Ionics 7 (2001) 109.Google Scholar
  2. 2.
    H. Ohta, W. S. Seo and K. Koumoto, J. Am. Ceram. Soc. 79 (1996) 2193.Google Scholar
  3. 3.
    M. Kazeoka, H. Hiramatsu, W. S. Seo and K. Koumoto J. Mater. Res. 13 (1998) 523.Google Scholar
  4. 4.
    Y. Masuda, M. Ohta, W. Pitschke, W. S. Seo and K. Koumoto, J. Solid State Chem. 150 (2000) 221.Google Scholar
  5. 5.
    T. Tsubota, M. Ohtaki, K. Eguchi and H. Arai, J. Mater. Chem. 7 (1997) 85.Google Scholar
  6. 6.
    I. Terasaki, Y. Sasago and K. Uchinokura, Phys. Rev. B 56 (1997) R12685.Google Scholar
  7. 7.
    M. Yasukawa and N. Murayama, J. Mater. Sci. Lett. 32 (1997) 1731.Google Scholar
  8. 8.
    S. Li, R. Funahashi, I. Matsubara, K. Ueno and H. Yamada, J. Mater. Chem. 9 (1999) 1659.Google Scholar
  9. 9.
    R. Funahashi, I. Matsubara and S. Sodeoka, Appl. Phys. Lett. 76 (2000) 2385.Google Scholar
  10. 10.
    R. Funahashi, I. Matsubara, S. Sodeoka, H. Ikuta, T. Takeuchi and U. Mizutani, Jpn. J. Appl. Phys. 39 (2000) L1127.Google Scholar
  11. 11.
    W. Shin and N. Murayama, ibid. 38 (1999) L1336.Google Scholar
  12. 12.
    W. Shin and N. Murayama, Matt. Lett. 45 (2000) 302.Google Scholar
  13. 13.
    Y. Fujishiro, M. Miyata, M. Awano and K. Maeda, Ceram. Int. 28 (2002) 841.Google Scholar
  14. 14.
    J. G. Kim, D. L. Pugmire, D. Battaglia and M. A. Langell, Appl. Surf. Sci. 165 (2000) 70.Google Scholar
  15. 15.
    D. P. Lapham, I. Colbeck, K. Schoonman and Y. Kamlag, Thin Solid Films 391 (2001) 17.Google Scholar
  16. 16.
    J. Molenda, P. Wilk and J. Marzec, Solid State Ionics 119 (1999) 19.Google Scholar
  17. 17.
    E. M. Levin, C. R. Robbins, H. F. Mcmurdie and M. K. Reser, “Phase Diagrams for Ceramists”, 4th edn. (American Ceramic Society, Ohio, USA, 1979) p. 52.Google Scholar

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Yoshinobu Fujishiro
    • 1
  • Kouich Hamamoto
    • 1
  • Osamu Shiono
    • 2
  • Shingo Katayama
    • 2
  • Masanobu Awano
    • 1
  1. 1.Research Center of Synergy Materials, AISTNagoyaJapan
  2. 2.Synergy Ceramics LaboratoryFine Ceramics Research Association (FCRA), Joint Research Center for Advanced TechnologyNagoyaJapan

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