Thermoelectric properties of layered Ca_3.95RE_0.05Mn₃O₁₀ compounds (RE = Ce, Nd, Sm, Eu, Gd, Dy)

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• 作者：S. Lemonnier ; E. Guilmeau ; C. Goupil ; R. Funahashi ; J.G. Noudem
• 关键词：Oxides ; Thermoelectric ; Resistivity ; Seebeck
• 刊名：Ceramics International
• 出版年：2010
• 出版时间：April 2010
• 年：2010
• 卷：36
• 期：3
• 页码：887-891
• 全文大小：552 K

文摘

In this work, polycrystalline samples of the substituted n = 3 Ruddlesden-Popper Ca_4−xRE_xMn₃O₁₀ phase were prepared by solid-state reaction (RE, rare earth = Ce, Nd, Sm, Eu, Gd, Dy). Single phased samples were synthesized for sintering times larger than 150 h at 1350 °C. Complete thermoelectric characterizations were performed from 5 to 390 K, in terms of electrical resistivity (ρ), Seebeck coefficient (S) and thermal conductivity (κ). As expected, the substitution of Ca by different rare earth elements leads to a significant modification of the thermoelectric properties. With substitution level as low as 1.25 at. % , a remarkable decrease of the electrical resistivity is observed. The influence of this cationic substitution on the thermal conductivity (κ), Seebeck coefficient (S), and the figure of merit ZT is also discussed. In this study, the best one reaches 5.8 × 10⁻³ at 300 K for the Ca_3.95Eu_0.05Mn₃O₁₀ composition, a value 6 times higher than the ZT exhibited by the beginning Ca₄Mn₃O₁₀ sample.