Eu doping effects on structural and magnetic properties of (Sr _2-xEu_x)FeMoO₆ compounds

Double perovskite compounds (Sr_2-xEu_x)FeMoO ₆ (0≤x≤0.3) were prepared by solid-state reaction at high temperature. Crystal structure, magnetic and transport properties of the compounds were investigated. The crystal structure of the compounds changes from an I4/m lattice to an Fm3̄m lattice around x=0.1. The unit-cell volume decreases with the doping level in both the I4/m lattice and the Fm3̄m lattice. The resistivity of the compounds shows a metalsemiconductor transition, and the transition temperature T_MS increases with the doping level. However, Curie temperature (T_C) of the compounds exhibits a weak dependence on the doping level. The saturation magnetization (M_S) at 100 K varies almost linearly with the anti-site defect concentration and agrees well with the simple FIM model. In contrast to the Ce-, Pr-, Nd- and Sm-doped Sr₂FeMoO₆, the difference of M_S of (Sr _2-xEu_x)FeMoO₆ between 5 and 100 K indicates that the moment of Eu³ is antiparellel to that of Fe³ at low temperature.