Cationic ordering control of magnetization in Sr2FeMoO6 double perovskite

The role of the synthesis conditions on the cationic Fe/Mo ordering in ${\mathrm{Sr}}_{\mathrm{2}}{\mathrm{FeMoO}}_{\mathrm{6}}$ double perovskite is addressed. It is shown that this ordering can be controlled and varied systematically. The Fe/Mo ordering has a profound impact on the saturation magnetization of the material. Using the appropriate synthesis protocol a value of 3.7 ${\mu }_B$ has been obtained. Mössbauer analysis reveals the existence of two distinguishable Fe sites and a charge density at the ${\mathrm{Fe}}^{\mathrm{m+}}$ ions significantly larger than ${\text{3d}}^5$ suggesting a Fe contribution to the spin-down conduction band. The implications of these findings for the synthesis of ${\mathrm{Sr}}_{\mathrm{2}}{\mathrm{FeMoO}}_{\mathrm{6}}$ having optimal magnetoresistance response are discussed.