Synthesis, characterization and thermoelectric properties of Ca substituted nanostructured SrMnO3 by sol-gel hydrothermal method

Abstract

Perovskite manganites are pure and stable at elevated temperatures due to its thermal and chemical stability. Pure and Ca substituted SrMnO3 nanoparticles have been prepared by sol-gel hydrothermal method. Structural, micro structural, elemental, functional, optical, electrical and thermoelectric properties have been investigated by XRD, Raman, SEM with EDAX, FTIR, UV–Vis Spectroscopy and Physical properties respectively. Powder X-ray Diffraction studies reveals the formation of the single phase without secondary phases. Poly vinyl pyrrolidone as a capping agent decreases the grain size of the nanoparticles with different nanostructures. Electrical conductivity increases but thermal conductivity is strongly reduced due to grain size reduction. Thermoelectric properties are evaluated from ambient to 300 K. Ca2+ substituted at A-site of SrMnO3 nanoparticles leads to oxygen deficient calcium manganese oxide nanoparticles. The major charge carriers are an electron that reveals that pure and Ca substituted SrMnO3 nanoparticles are n-type promising thermoelectric oxides with high thermoelectric power.