Characterization of ferromagnetic double perovskite Sr2FeMoO6 prepared by various methods

Tetragonal Sr2FeMoO6 powders were prepared by the sol-gel and solid-state reaction methods. The structure, microstructure and magnetic characteristics of the double perovskite Sr2FeMoO6 in the form of as-prepared powders and classical sintered ceramics were analyzed and compared. Moreover, the magnetic properties of Sr2FeMoO6 ceramics obtained by sol-gel and solid state reaction methods and sintered by the classical method were compared with those of Sr2FeMoO6 ceramics obtained by the same two methods, but sintered by the spark plasma sintering technique. The morphology of the powders obtained from the gel precursor and oxides mixture was characterized by homogeneity, as well as the grains shape and size. The powder prepared by the sol-gel method was finer (particle average size of 0.6 µm) than those obtained from oxides mixture (particle average size of 0.9 µm). Sintered ceramics with tetragonal Sr2FeMoO6 phase were prepared from the two mentioned powders by classical sintering at 1200 °C, 2 h in 5%H2/Ar. The pellets obtained from the gel powder exhibited higher magnetic characteristics than those derived from the oxides mixture. The saturation magnetization and the total magnetic moment of the samples prepared by the sol-gel method were Msat=41.18 emu/g and µexp/f.u.=3.26, respectively, while for the samples derived from the oxides mixture were Msat=40.77 emu/g and µexp/f.u=3.10. Also, Sr2FeMoO6 pellets sintered by the conventional method showed higher saturation magnetization values than those sintered by spark plasma sintering technique.