Effect of the Yb substitutions on the thermoelectric properties of CaMnO3

Ca1-xYbxMnO3 (x = 0.05) samples were prepared via solid state reaction in air. Electrical and thermoelectric properties have been investigated up to 1000K. The measurements reveal that the resistivity values are strongly affected by the charge carrier content and the octahedral distortion. The lowest p reaches 3m Omega.cm for x=0.15. Whereas the Seebeck coefficient depends only on the charge carrier concentration, the thermal conductivity of Ca1-xYbxMnO3 is mainly governed by the mass difference between the Yb and Ca cations. The best ZT value, ZT=0.2, is obtained for x=0.05 at 1000K and demonstrates the good potentialities of these oxides as high temperature thermoelectric material.