Effect of gas flow rate on transport properties of Sr2FeMoO6

Sr2FeMoO6 (SFMO) was synthesized by sol-gel method under different gas flow rate of 5% H-2/Ar (S1: 30 ml/min, S2: 45 ml/min, S3: 55 ml/min). The crystal structures of S1, S2 and S3 were tested and analyzed by X-ray diffraction (XRD). It was found that S1, S2 and S3 were pure phase and the space group was I4/m. It can be seen from the transport characteristic curve that the pellets show semiconductivity without magnetic field. Under magnetic field, the pellet S1 still show semiconductive behavior, while the two pellets S2 and S3 show metallicity, which is mainly related to anti-site defect (ASD), crystallinity of the pellets and oxygen vacancies. Under low temperature of 5 K, the pellets have obvious ferromagnetism and small coercive field, and their saturation magnetic moments are 3.16 mu(B)/f.u, 3.44 mu(B)/f.u, 2.79 mu(B)/f.u, the coercive field sizes are 63.94 Oe, 65.95 Oe, 76.38 Oe, respectively.