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Structural analysis and thermoelectric properties of Type-I clathrate compounds in the Ba-Ge-Ga system

Published online by Cambridge University Press:  01 February 2011

Norihiko L. Okamoto ,
Takumi Nishii ,
Min Wook Oh  and
Haruyuki Inui
Norihiko L. Okamoto
Affiliation:
Department of Materials Science and Engineering, Kyoto University Sakyo-ku, Kyoto 606–8501, Japan
Takumi Nishii
Affiliation:
Department of Materials Science and Engineering, Kyoto University Sakyo-ku, Kyoto 606–8501, Japan
Min Wook Oh
Affiliation:
Department of Materials Science and Engineering, Kyoto University Sakyo-ku, Kyoto 606–8501, Japan
Haruyuki Inui
Affiliation:
Department of Materials Science and Engineering, Kyoto University Sakyo-ku, Kyoto 606–8501, Japan
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Abstract

The crystal structure and thermoelectric properties of Type-I clathrate compounds in the Ba-Ge-Ga system (Ba8GaXGe46-X) have been investigated as a function of Ga content. While all ternary compounds containing more than 3 Ga exhibit a crystal structure of normal Type-I clathrates with the space group Pm 3 n, the binary compound possesses a composition Ba8Ge43, which is leaner in Ge than the stoichiometric composition, and has a crystal structure different from that of normal Type-I clathrates because of the ordering of Ge vacancies in 6c sites of the parent normal Type-I clathrate structure. The temperature dependence of electrical resistivity of binary Ba8Ge43 is of semiconductor while that for all the ternary compounds is metallic. The value of Seebeck coefficient increases with the increase in the Ga content. The value of dimensionless figure of merit (ZT) increases with the increase in the Ga content, exhibiting a high value of 0.76 at 700°C for Ba8Ga16Ge30.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 793: Symposium S – Thermoelectric Materials 2003 - Research and Applications , 2003 , S7.6
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

1. Nolas, G. S., Mater. Res. Soc. Symp. Proc. 545, 435 (1999).Google Scholar
2. Nolas, G. S., Vanderveer, D. G., Wilkinson, A. P. and Cohn, J. L., J. Appl. Phys. 91, 8970 (2002).Google Scholar
3. Kim, S.-J., Hu, S., Uher, C., Hogan, T., Huang, B., Corbett, J. D. and Kanatzidis, M. G., J. Solid State Chem. 153, 321 (2000).Google Scholar
4. Slack, G. A., in CRC Handbook of Thermoelectrics, edited by Rowe, D. M. (CRC Press, Boca Raton, 1995) p. 407.Google Scholar
5. Herrmann, Rüdinger F. W., Tanigaki, Katsumi, Kawaguchi, Tetsuji, Kuroshima, Sadanori and Zhou, Otto, Phys. Rev. B 60, 13245 (1999).Google Scholar
6. Izumi, F. and Ikeda, T., Mater. Sci. Forum, 321–324, 198–203 (2000).Google Scholar
7. Cabrera, Wilder C., Borrmann, Horst, Michalak, Rüdiger and Grin, Yuri, on the website; http://pc176.ph.rhul.ac.uk/~grosche/presentations/ba6ge25struc.pdf Google Scholar
8. Lide, David R., Handbook of Chemistry and Physics, 82nd ed. (CRC press, Boca Raton, Florida, 2001).Google Scholar
9. Nolas, G. S., Cohn, J. L., Slack, G. A. and Schujman, S. B., Appl. Phys. Lett. 73, 178 (1998).Google Scholar