The low-temperature thermoelectric properties of Ca3-xYbxCo4O9+delta systems (x = 0, 0.02, 0.05, and 0.10). It was determined that these systems produced positive thermopower, indicating that the dominant carriers were holes. The electrical resistivity and thermopower were found to increase with increasing Yb3+ content, and the thermal conductivity was found to decrease. The highest calculated thermoelectric figure of merit was 0.037, and this was calculated for the Ca2.95Yb0.05Co4O9+delta sample....
Calcium is partially substituted by bismuth in the Ca3-xBixCoO9+delta (x=0.00, 0.05, 0.10, 0.15, 0.20, and 0.30) system in order to determine how this substitution affects the thermoelectric and magnetic properties of the system. It was determined that the system had a positive thermopower, and thus the main carriers were holes. A maximum thermoelectric figure of merit of 0.091 was achieved with the Ca2.7Bi0.3CoO9+delta sample. The magnetic property test results indicated that ...
Calcium is partially substituted by bismuth in the Ca1-xBixMnO3-delta (x=0.00, 0.02, and 0.05) system in order to determine how this substitution affects the electrical resistivity, thermopower, and thermal conductivity. The experimental results were then used to calculate the thermoelectric figure of merit for each sample. The highest observed figure of merit was 0.047, which represented a 487% increase over the unsubstituted sample....
Thermoelectric materials are currently being researched as a source of energy in order to reduce carbon dioxide emissions. The efficiency of these materials depends on their Seebeck coefficient, electrical resistivity, and thermal conductivity, as well as the absolute temperature. Cobalt oxides (Ca3Co4O9+delta) have been researched extensively as potential thermoelectric materials because of their high Seebeck coefficient and low electrical resistivity and thermal conductivity. Systems have been studied ...
Samples of Ca0.98RE0.02MnO3- delta (RE = Sm, Gd, and Dy) were tested for their thermoelectric and magnetic properties. It was determined that 2% doping at the Ca site with rare-earth elements reduced the electrical resistivity and thermal conductivity in comparison to the undoped material....
