High-pressure synthesis of the double perovskiteSr2FeMoO6: increment of the cationic ordering and enhanced magnetic properties

Abstract

The double perovskite Sr2FeMoO6 has been prepared in polycrystalline form by high-pressure methods, starting from aprecursor developed via a citrate technique, containing an elevated degree ofanti-site disordering. The application of high external pressure (2 GPa) toSr2FeMoO6 promotes the long distance Fe/Mo cationic order, due to the smaller lattice volume of theordered sample. Both the disordered perovskite obtained at ambient pressure and thesample synthesized under high-pressure methods have been characterized by means of x-raydiffraction, neutron powder diffraction and magnetic measurements. The magneticproperties of the two oxides have been compared; the specimen prepared under highpressure not only presents an improved cationic ordering, but also displays a superiorsaturation magnetization and a sharpener ferromagnetic transition at a significantly hightemperature of 430 K.