Abstract
We have synthesized single- and polycrystal Ba8AlxSi46−x clathrates to compare their thermoelectric properties. Single-crystal sample was prepared by Czochralski method in an argon atmosphere. Polycrystal sample was prepared by arc melting and annealed at 850 °C for 100 h in an argon atmosphere. The Seebeck coefficients of single- and polycrystal Ba8Al12Si34 at 500 °C were 44.5 and 53.0 μV/K, respectively. The Seebeck coefficients of both samples were almost the same because the Seebeck coefficients depend on carrier concentration, which is related to aluminum content. The electrical resistivity of the single-crystal sample with 0.49 mΩcm was lower than that of the polycrystal sample with 0.95 mΩcm because of the reduction of electron scattering. Therefore, the power factor of the single-crystal sample with 4.0 × 10−4 V2/K2Ωm was higher than that of the polycrystal sample with 3.0 × 10−4 V2/K2Ωm at 500 °C. It is suggested that single crystallization is efficient for improvement of the thermoelectric property in the Ba8AlxSi46−x clathrate.
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Mugita, N., Nakakohara, Y., Teranishi, R. et al. Single crystallization of Ba8AlxSi46−x clathrate for improvement of thermoelectric properties. Journal of Materials Research 26, 1857–1860 (2011). https://doi.org/10.1557/jmr.2011.193
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DOI: https://doi.org/10.1557/jmr.2011.193