Structural and magnetic properties of rare-earth doped (Sr2−xSmx)FeMoO6 compounds

Electron doped double perovskite compound (Sr2−xSmx)FeMoO6 (0≤x≤0.25) has been synthesized by solid-state reaction at high temperature. Crystal structure and magnetic properties of the compounds have been investigated by X-ray powder diffraction (XRD) and magnetic measurements. XRD revealed that all the compounds were of single phase and belonged to a I4/m lattice. The degree of cationic ordering on the B site was decreased pronouncedly by the electron doping. Different from the results of La- and Nd-doped Sr2FeMoO6, Curie temperature (TC) of (Sr2−xSmx)FeMoO6 decreased first with the doping and then increased beyond x=0.15, indicating that steric effect was enhanced as the radius of rare-earth ions decreased. Saturation magnetization (MS) of the compounds decreased with the doping level and anti-site (AS) concentration. Sm moment showed a considerable contribution to MS at low temperature, leading to an abrupt drop of MS between x=0.1 and 0.15.