Abstract
Manganites had been proposed as one of the potential n-type oxide materials to develop thermoelectric power generators. In the present investigation, we studied the structural and thermoelectric properties of Gd1-xSrxMnO3 (GSMO) (0.5 <= x <= 0.8) polycrystalline ceramics synthesized by a conventional solid-state route. Rietveld refinement of XRD patterns revealed the distorted ortho-rhombic Pbnm crystal structure in all the compositions. The decrease in J-T distortions, present on the Gd-rich side of GSMO (x <= 0.6), due to favored formation of Mn4+ was calculated. Thermoelectric properties such as Seebeck coefficient (S) and electrical conductivity (sigma) of these ceramics were measured in the temperature range from room temperature to 900 degrees C. The negative values of the Seebeck coefficient throughout the temperature range confirm the n-type semiconducting nature in all the compositions. The conduction mechanism (below metal-semiconductor transition) of these materials was analyzed using the small polaron hopping conduction model. Published by AIP Publishing.