Abstract
The present work deals with the synthesis, characterization, and thermoelectric properties of La2-xPrxFeCoO6 (x = 0.0, 0.25, 0.50, 0.75, and 1.0) ceramics. The crystal structure, microstructural characteristics, electrical properties, and thermal transport characteristics of the sintered samples were studied. The samples prepared by sol-gel technique resulted in the presence of nanocrystalline single phase material after 6 hrs of calcination, and the increased crystallite size with increasing Pr concentration alongwith the occurrences of multivalent oxidation states of La, Pr, Fe, Co and O. The conductivity investigation revealed the presence of a nearest neighbor hopping charge carrier conduction mechanism in the entire samples, i.e., an increasing Pr-content result in enhanced conductivity at every examined temperature. For the entire composition range (x), conductivity increases with increasing temperature up to maximum value at a transition temperature followed by a downward trend, indicating the metallic behavior (reduction in semiconducting behavior) due to the presence of oxygen deficiency at higher temperature. Positive S values indicate the presence of p-type charge carrier in La2-xPrxFeCoO6 double perovskite and intrinsic behavior was conserved with increasing doping concentration (x). Temperature dependent power factor increases with increasing Pr-content and the maximum values were observed at their transition temperatures. Within recorded temperature, the highest Figure of Merit (ZT = ∼0.87) was observed at x = 1.0 in La2-xPrxFeCoO6 compound, which was 5.4 times more as compare to x = 0.0.
[Display omitted]
•Pr-doped La2-xPrxFeCoO6 ceramics (x = 0 to 1) were synthesized by sol-gel technique.•The grain size increased with increase of Pr-doping concentration.•σ, PF and ZT increases due to increase of charge carrier with temperature.•The highest σ and ZT were 18.48 S cm−1 and 0.87 respectively, at x = 1.•With increasing x, enhanced properties were seen at every examined temperature.