Reaction kinetics of the double perovskite Sr2FeMoO6 by gas–solid reactions

Double perovskite Sr2FeMoO6 is characterized by its colossal magnetoresistance, however, its production route is not well established. Therefore, the objective of this work is to study the reaction kinetics involved in the formation of Sr2FeMoO6. Firstly, precursor phases Sr2Fe2O5 and SrMoO4 were synthesized by gas-solid reactions from starting reagents such as SrCO3, Fe2O3 y MoO3. The thermogravimetric technique was employed to analyze the kinetics of formation of the double perovskite from the precursor phases given the optimized process variables. Microstructural characterization of the products obtained was performed by X-ray diffraction and Rietveld analysis. Results showed that the instability of SrFeO2.5 during the reduction stage led to a formation of a disordered double perovskite Sr2Fe0.71Mo1.29O6.