Effect of Sr-doping on electronic and thermal properties of Pr2-xSrxFeCrO6 (0≤x≤1) oxide materials synthesized by using sol-gel technique

Abstract

ABSTRACT The thermoelectric properties of a new type of Pr2-xSrxFeCrO6 double perovskite were investigated at higher temperature after its sol-gel synthesis. The XRD results validate the single-phase orthorhombic structure, and the crystallite sizes meet the morphological measurements. XPS examination, which formed the defect sites in these oxides, confirmed the varied oxidation states of constituents. The temperature-dependent electrical conductivity (σ) was poor in the original Pr2FeCrO6 composition, but after substituting Sr on the Pr-site, a significant rise in σ with two semiconductors and one metal transition was observed. A positive Seebeck coefficient confirmed the presence of a p-type charge carrier in the entire composition, and the charge transport mechanism was driven by the SPH model. Thermal conductivity increases in all doped samples, while it decreases in pristine compounds over the broad analyzed temperature range. Thermal expansion coefficient increased after doping in oxygen-deficient compound. The PrSrFeCrO6 compound had the maximum ZT (0.105), which was 3.9 times higher than that of the pristine compound.