Effects of vacancy doping at the Mo site on the magnetic property of double perovskite Sr2FeMoO6

Sr2FeMo(1-x)O6 (X = 0.00, 0.01, 0.03, and 0.04) samples were prepared by sol-gel method, and the effects of Mo vacancy on the structural, magnetic, and transport properties of these materials were studied. XRD results showed that all samples had a single phase and belonged to the I4/m space group. Scanning electron micrographs indicated that the particle sizes of samples with X = 0.00, 0.01, 0.03, and 0.04 were 1.26, 1.32, 1.27, and 1.19 μm, respectively. The curve of the resistivity measured by PPMS versus temperature demonstrated that all samples behaved as semiconductors. The curves of the field-cooled and isothermal magnetization of the samples showed ferromagnetic to paramagnetic transition. Under magnetic field at 2.5 T, the maximum changes in the magnetic entropy of the samples were 0.53, 0.6, 0.58, and 0.57 J kg−1K−1, respectively.