Magnetic properties, resistivity and magnetoresistance effects of double perovskite La2Co1−xFexMnO6

Double perovskite La2Co1−xFexMnO6 (x = 0.1, 0.2, 0.5, 1.0) ceramic samples were synthesized by the standard solid-state reaction method. The powder x-ray diffraction (Cu-Kα) results confirm that this type of compounds has orthorhombic perovskite structure with space group of Pbnm at room temperature. The exchange bias can be observed in all samples. The random distribution of the Fe3+ ions increases the disorder in La2Co1−xFexMnO6 system, which leads the decreasing of Curie temperature, coercive field, saturation magnetization and remanent magnetization. Griffiths phase may exist below certain temperature in La2Co1−xFexMnO6 samples. The electrical resistivity of La2Co1−xFexMnO6 exhibits obvious semiconducting-like behavior, while the conduction model gradually changed from 3-dimensional variable range hopping model to thermal activation model with the increasing of Fe3+-substitution. The negative magnetoresistance effects observed in all samples may be suppressed by Fe3+-substitution.