Synthesis, magnetic and electrical transport properties of magnetoresistance material Sr2FeMoO6 by microwave sintering

Magnetoresistance material Sr2FeMoO6 with double perovskite structure was synthesized by microwave sintering method using SrCO3, Fe2O3 and MoO3 as raw materials, with MnO2 for microwave absorber. The phase structure, magnetic and electrical transport properties were investigated by X-ray powder diffraction (XRD) and vibrating-sample magnetometer. XRD analysis shows that the as-synthesized sample is Sr2FeMoO6 with tetragonal crystal structure and 14/mmm space group. The unit cell parameters are a=0.5587 nm, c=0.7894 nm, volume=0.2464 nm(3). The calculated grain size of the sample is 31.62 nm, which is obtained by the Scherrer formula using the diffraction data. Magnetism testing results show that the sample Sr2FeMoO6 is ferromagnetic with the magnetic transition temperature of about 380 K. Under 1.0 T magnetic field, the saturation and spontaneous magnetization of Sr2FeMoO6 is 1.25 mu(B)/f.u. and 1.00 mu(B)/f.u. at room temperature. The magnetoresistance ratio of the sample is 28%. Electrical transport properties testing results indicate that the sample exhibits typical semiconductor behavior. The conductive mechanism of Sr2FeMoO6 is highly dependent on temperature: within the temperature range of 100-300 K, the mechanism is attributed to the small polaron variable-range hopping model; while it is ascribed to the adiabatic small polaron model within the temperature range of 80-100 K. (C) 2012 Elsevier B.V. All rights reserved.