The thermoelectric properties of Ca3-xYbxCo3.95Ga0.05O9+delta where x = 0.00, 0.02, 0.05, and 0.10 were determined at temperatures less than 300 K. It was determined that the partial substitution of Yb3+ for Ca2+ resulted in an increase in resistivity and thermopower. The thermal conductivity was found to decrease with increasing Yb3+ content, and the sample producing the highest thermoelectric figure of merit at 300 K was the x = 0.05 sample....
The thermoelectric properties of the Ca1-xGdxMnO3-delta system where x= 0.00, 0.02, and 0.05 were evaluated. It was determined that the sample with the lowest electrical resistivity was the Ca0.95Gd0.05MnO3-delta sample. This result was attributed to the increase content of Mn3+ in the Mn4+ matrix resulting from doping of gadolinium. The dominant charge carriers in all samples were holes, as the thermopower was negative. The highest thermoelectric figure of ...
The partial replacement of Ca2+ ions with Eu3+ in the Ca3Co3.95Ga0.05O9+delta system to give polycrystalline samples of Ca3-xEuxCo3.95Ga0.05O9+delta (x = 0.00, 0.02, and 0.10) was performed in order to assess the effect that the dopant had on thermoelectric properties of this system. It was found that the electrical resistivity and thermopower increased with increasing Eu3+ content, and the thermal conductivity decreased. The highest thermoelectric figure of ...
The partial replacement of Ca2+ ions with Eu3+ in the Ca3Co3.95Ga0.05O9+delta system to give polycrystalline samples of Ca3-xEuxCo4O9+delta (x = 0.00, 0.05, and 0.10) was performed in order to assess the effect that the dopant had on thermoelectric properties of this system. It was found that the electrical resistivity and thermopower increased when Eu3+ is added, and the thermal conductivity decreased. The highest thermoelectric figure of merit ...
Two series of co-doped mifit-layered cobaltites were prepared with compositions of Ca3-xYbxCo4-yAgyO9+delta and Ca3-xEuxCo4-yAgyO9+delta. All of the samples exhibited an increasing thermopower as temperature was increased up to a temperature of 700 K. The sample with the highest power factor and figure of merit was Ca2.95Eu0.05Co3.95Ag0.05O9+delta....
