Magnetocaloric effect and magnetic properties of the isovalent Sr2+ substituted Ba2FeMoO6 double perovskite

Fine-tuning the charge distribution in Ba2FeMoO6 obtained via “isovalent” substitution at the A-site (i.e., Ba) is expected to bring about changes in the physical properties of the system that can be manipulated in magnetic refrigerants. With this motivation, the phase formation, crystal structure, microstructure, magnetic and magnetocaloric properties of the Ba2−xSrxFeMoO6 (0≤x≤0.4) samples fabricated by solid state reaction method have been investigated. The X-ray diffraction analysis confirmed the formation of cubic structure with Fm3m space group in all the fabricated samples. The magnetization measurements and Arrott analysis revealed a second order of ferromagnetic phase transition in all the samples. An increase in magnetization and Curie temperature (TC) was observed with the increase in Sr-content that was attributed to the increased orbital hybridization and exchange interaction between Fe and Mo ions. The magnitude of the maximum magnetic entropy change at the Curie temperature and the relative cooling power were observed to slightly decrease with the increased Sr doping. The excellent magnetocaloric features and convenient adjustment of Curie temperature make these materials useful for magnetic refrigeration in a wide range of temperature.