Effects of Ni doping on B-site ordering and magnetic behaviors of double perovskite Sr2FeMoO6

Sr2FeMoO6 of double perovskite structure has attracted much attention recently, owing to its substantial low-field magnetoresistance reported at room temperature. In our study, a mechanical activation process is devised for successful formation of Ni-doped double perovskite Sr-2(Fe1-xNix )MoO6 (0.00 <= x <= 0.20). For the first time, a single phase of double perovskite is synthesized in air by using MoO2 as the starting material. Ni doping in Sr2FeMoO6 significantly affects its long-range B-site ordering and magnetic behaviors, where the B-site long-range order parameter is progressively enhanced with increasing Ni doping level. Both magnetization and the Curie temperature in Sr2FeMoO6 are enhanced significantly by Ni doping, where they both depend almost linearly on the degree of B-site long-range ordering.