Enhancement of Curie temperature and room-temperature magnetoresistance in double perovskite (Sr1.6Ba0.4)FeMoO6

The effects of A-site average cation size 〈rA〉 and anti-site defects on Curie temperature (TC) and room-temperature magnetoresistance (MR) in (Sr2−xBax)FeMoO6 (x=0, 0.4 and 1.6) have been investigated. By Ba doping, not only the room-temperature MR but also the TC have been enhanced. The larger MR in the Ba-doped samples compared with the prototype Sr2FeMoO6 is associated with the lower saturation field. The optimization of TC and MR in (Sr1.6Ba0.4)FeMoO6 other than in the reported (Sr0.4Ba1.6)FeMoO6 can be understood according to the two competing effects: anti-site defects and chemical pressure.