Influence of rare-earth elements doping on thermoelectric properties of Ca0.98Dy0.02MnO3 at high temperature

• Ca0.96Dy0.02Re0.02MnO3 (Re=La, Pr, …, Yb) are produced by solid state reaction.
• Lowest resistivity is obtained due to the highest carrier mobility for Re=Yb.
• Highest power factor obtained is 415 μW/(K2m) at 973 K for Re=Yb.
• Highest ZT value obtained is 0.25 at 973 K for Ca0.96Dy0.02Yb0.02MnO3 sample.

Ca0.98Dy0.02MnO3 and Ca0.96Dy0.02Re0.02MnO3 (Re=La, Pr, Sm, Eu, Ho, and Yb) have been synthesized by the solid state reaction method. Samples with relative densities all over 96% have been obtained. Thermoelectric properties are evaluated between 300 and 1000 K. The electrical resistivity shows a typical metal-like conductivity behavior, and at high temperature, 973 K, decreases from 36.1 mΩ cm for Ca0.98Dy0.02MnO3 to 8.6 mΩ cm for Ca0.96Dy0.02Yb0.02MnO3. Both the absolute values of Seebeck coefficient and thermal conductivity are reduced by the introduction of second rare-earth element. The highest power factor of 415 μW/(K2m) is obtained for Ca0.96Dy0.02Yb0.02MnO3 sample, resulting in the highest dimensionless figure of merit (ZT) 0.25 at 973 K. This value shows an improvement of 144% compared with that of Ca0.98Dy0.02MnO3 ceramics at the same temperature.

The Ca0.96Dy0.02Re0.02MnO3 (Re=La, Pr, …, Yb) were prepared by solid state reaction. Highest ZT value obtained is 0.25 at 973 K for Re=Yb, which shows 144% improvement compared with Ca0.98Dy0.02MnO3. Figure optionsDownload as PowerPoint slide