| Sumario: | Nb-doped Ca0.97Y0.01La0.01Yb0.01Mn1-xNbxO3 materials were prepared to assess their thermoelectric properties. Samples were obtained by sintering at 1583 K for 12 h involving planetary milled precursors. XRD analysis indicated primarily thermoelectric phase with minor CaMn2O4. Microstructural observations revealed decreasing grain size with increasing Nb content. However, electrical resistivity decreases for the samples with Nb-content up to 0.03, which can be associated with the increase of the charge carrier concentration. The lowest value at 1073 K (9.2mΩcm) is among the best reported in the literature. Seebeck coefficient decreased with Nb-doping, and the best PF value at 1073 K has been determined for 0.01Nb samples (∼0.48mW/K2m). Assuming the thermal conductivity at 1073 K similar to that at 473 K, the calculated ZT values are among the typically reported in this family. These results highlight the promise of CaMnO3-based materials for integration in thermoelectric modules working under steady-state mode, where the high PF values are of great importance.
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