Antisite disorder-induced low-field magnetoresistance in some frustrated Sr2FeMoO6

Considering the existence of antiferromagnetic patches induced by the antisite disorder in ferrimagnetic Sr2FeMoO6, we have developed a resistor network model to account for the effects of the antisite disorder on the magnetoresistance in this material. It is proposed that the magnetic disorder resulting from the existence of frustration around the antiferromagnetic patches will be suppressed under the applied magnetic field and low-field magnetoresistance will be observed. For samples with low levels of antisite defects, the magnetoresistive behaviour may be strongly affected by the different degrees of magnetic inhomogeneity. Our calculated results are in agreement with experimental observations