The annealing effects on the crystal structure, magnetism and microstructure of the ferromagnetic double perovskite Sr2FeMoO6 synthesized via spark plasma sintering

Double perovskite Sr2FeMoO6 (SFMO) has drawn great attention because of its colossal magnetoresistance at room temperature and promising potential applications in solid oxide fuel cells as an anode material. In this study, the polycrystalline SFMO was prepared by spark plasma sintering (SPS) and its crystal structure, microtopography, magnetic properties, spin-glass phase and anti-site defects were investigated in detail. The effects of the annealing process on the physical properties of the SPS sample were detailedly discussed and studied. The annealing process can effectively suppress the spin-glass phases and impurity phase SrMoO4, and simultaneously increase the content of SFMO phases. Besides, the low-temperature magnetic behaviors were confirmed by the field cooling (FC), zero field cooling (ZFC) DC magnetic susceptibility and AC magnetic susceptibility. The TEM results confirm that the annealing process can effectively suppress the impurity phase SrMoO4, simultaneously increase the size of the SFMO crystal grains and improve the homogeneity of the crystal grains. This systematic study of double perovskite SFMO will facilitate its potential applications in the field of spin electronics.