Magnetoresistance in double perovskites Ba2-xLaxFeMoO6

We have studied effects of the partial substitution of La3+ for Ba2+ on the magnetoresistance (MR) in Ba2FeMoO6. The substitution of La3+ for Ba2+ results in the increase of antisite disorder which reduces the magnetic moment. The magnitude of MR of Ba2FeMoO6 is greatly reduced by La doping. The MR with low magnetic field of 7 kOe for x = 0 and 0.5 are 5% and 0.5% at room temperature, respectively. These phenomena are explained in terms of an intergrain tunneling at grain boundary and a spin dependent crossing of intragranular barrier originated from antisite disorder. (C) 2006 Elsevier B.V. All rights reserved.