Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-14T07:02:52.351Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Terasaki, I., Sasago, Y. and Uchinokura, K.: Large thermoelectric power in NaCo2O4 single crystals. Phys. Rev. B 56, R12685 (1997).CrossRefGoogle Scholar
2Fujita, K., Mochida, T. and Nakamura, K.: High-temperature thermoelectric properties of NaxCoO2−δ single crystals. Jpn. J. Appl. Phys. 40, 4644 (2001).CrossRefGoogle Scholar
3Funahashi, R., Matsubara, I., Ikuta, H., Takeuchi, T., Mizutani, U. and Sodeoka, S.: An oxide single crystal with high thermoelectric performance in air. Jpn. J. Appl. Phys. 39, L1127 (2000).CrossRefGoogle Scholar
4Funahashi, R., Matsubara, I.,  Ikuta, H.,  Takeuchi, T. and Mizutani, U.: Thermoelectric properties of (Ca, Sr, Bi)2Co2O5 whiskers. Mater. Trans. 42, 956 (2001).CrossRefGoogle Scholar
5Shikano, M. and Funahashi, R.: Electrical and thermal properties of single-crystalline (Ca2CoO3)0.7CoO2 with a Ca3Co4O9 structure. Appl. Phys. Lett. 82, 1851 (2003).CrossRefGoogle Scholar
6Funahashi, R. and Matsubara, I.: Thermoelectric properties of Pb- and Ca-doped (Bi2Sr2O4)xCoO2 whiskers. Appl. Phys. Lett. 79, 362 (2001).CrossRefGoogle Scholar
7Funahashi, R. and Shikano, M.: Bi2Sr2Co2Oy whiskers with high thermoelectric figure of merit. Appl. Phys. Lett. 81, 1459 (2002).CrossRefGoogle Scholar
8Hébert, S., Lambert, S., Pelloquin, D. and Maignan, A.: Large thermopower in a metallic cobaltite: The layered Tl–Sr–Co–O misfit. Phys. Rev. B 64, 172101 (2001).CrossRefGoogle Scholar
9Ishikawa, R., Ono, Y., Miyazaki, Y. and Kajitani, T.: Low-temperature synthesis and electric properties of new layered cobaltite, SrxCoO2. Jpn. J. Appl. Phys. 41, L337 (2002).CrossRefGoogle Scholar
10Singh, J.: Electronic structure of NaCo2O4. Phys. Rev. B 61, 13397 (2000).CrossRefGoogle Scholar
11Asahi, R., Sugiyama, J. and Tani, T.: Electronic structure of misfit-layered calcium cobaltite. Phys. Rev. B 66, 155103 (2002).CrossRefGoogle Scholar
12Takeuchi, T., Kondo, T., Takami, T., Takahashi, H., Ikuta, H., Mizutani, U., Soda, K., Funahashi, R., Shikano, M., Mikami, M., Tsuda, S., Yokoya, T., Shin, S. and Muro, T.: Contribution of electronic structure to the large thermoelectric power in layered cobalt oxides. Phys. Rev. B 69, 125410 (2004).CrossRefGoogle Scholar
13Terasaki, I., Tsukada, I. and Iguchi, Y.: Impurity-induced transition and impurity-enhanced thermopower in the thermoelectric oxide NaCo2−xCuxO4. Phys. Rev. B 65, 195106 (2002).CrossRefGoogle Scholar
14Masset, A.C., Michel, C., Maignan, A., Hervieu, M., Toulemonde, O.,  Studer, F. and  Raveau, B.: Misfit-layered cobaltite with an anisotropic giant magnetoresistance: Ca3Co4O9. Phys. Rev. B 62, 166 (2000).CrossRefGoogle Scholar
15Miyazaki, Y., Kudo, K., Akoshima, M., Ono, Y., Koike, Y. and Kajitani, T.: Low-temperature thermoelectric properties of the composite crystal [Ca2CoO3.34]0.614. CoO2. Jpn. J. Appl. Phys. 39 L531 (2000).CrossRefGoogle Scholar
16Ziman, J.M.: Principles of the Theory of Solids, 2nd ed. (Cambridge Univ. Press, Cambridge, UK, 1972), pp. 231, 243.CrossRefGoogle Scholar
17Vidyasagar, K., Gopalakrishnan, J. and Rao, C.N.R.: A convenient route for the synthesis of complex metal-oxides employing solid-solution precursors. Inorg. Chem. 23, 1206 (1984).CrossRefGoogle Scholar
18Fouassier, C., Matejka, G., Reau, J-M. and Hagenmuller, P.: On new bronze oxides of formula NaxCoO2 (x ⩽ 1). System cobalt oxygen-sodium. J. Solid State Chem. 6, 532 (1973).CrossRefGoogle Scholar
19Von-Jansen, M. and Hoppe, R.: Notiz zur Kenntnis der Oxocobaltate des Natriums. Z. Anorg. Allg. Chem. 408, 104 (1974).CrossRefGoogle Scholar
20Cushing, B.L., Falster, A.U., Simmons, W.B. Jr. and Wiley, J.B.: A multivalent ion exchange route to lamellar calcium cobalt oxides, CaxCoO2 (x ⩽ 0.5). J. Chem. Soc. Chem. Commun. 23, 2635 (1996).CrossRefGoogle Scholar
21Cushing, B.L. and Wiley, J.B.: Topotactic routes to layered calcium cobalt oxides. J. Solid State Chem. 141, 385 (1998).CrossRefGoogle Scholar
22Hatta, I., Sasuga, Y., Kato, R. and Maesono, A.: Thermal-diffusivity measurement of thin-films by means of an AC calorimetric method. Rev. Sci. Inst. 56, 1643 (1985).CrossRefGoogle Scholar
23Yamane, T., Mori, Y., Katayama, S. and Todoki, M.: Measurement of thermal diffusivities of thin metallic films using the ac calorimetric method. J. Appl. Phys. 82, 1153 (1997).CrossRefGoogle Scholar
24Shikano, M., Funahashi, R., Kitawaki, M., Sano, T., and Urata, S.: Thermoelectric properties of single crystalline Ca-Co-O system II. Extended Abstracts (The 63rd Autumn Meeting, 2002), the Japan Society of Applied Physics, 181 (2002).Google Scholar
25Huang, X.Y., Miyazaki, Y. and Kajitani, T.: Single crystal growth of electrical transport properties of β-Cax/CoO2 (x = 0.5). Extended Abstracts (The 52nd Spring Meeting, 2005), the Japan Society of Applied Physics and Related Societies, 251 (2005).Google Scholar