Effects of electron doping on the structure and magnetic properties in Ca2−xCexFeMoO6 double perovskites

A sol–gel method has been used to prepare a series of polycrystalline Ca2−xCexFeMoO6 (x = 0–0.4) double perovskites. Rietveld refinement of X-ray diffraction data indicates that although cell parameters increase slightly, the symmetry of the crystalline structure is preserved upon Ce doping. The partial substitution of Ce3+ for Ca2+ reduces the saturation magnetization, however it considerably enhances the Curie temperature (TC) from 365 K for x = 0 to 393 K for x = 0.4. Transport measurement shows that Ca2−xCexFeMoO6 exhibits metallic behavior, and the resistivity of Ca2−xCexFeMoO6 increases first, and then decreases with the increasing of x. The behavior of the increasing of TC and the decreasing of resistivity upon Ce doping was explained by the electron doping effects.