Enhancement of Curie temperature and room-temperature magnetoresistance in double perovskite (Sr_(1.6)Ba_(0.4))FeMoO_6

摘要

The effects of A-site average cation size and anti-site defects on Curie temperature (T_C) and room-temperature magnetoresistance (MR) in (Sr_(2-x)Ba_x)FeMoO_6 (x = 0, 0.4 and 1.6) have been investigated. By Ba doping, not only the room-temperature MR but also the T_C have been enhanced. The larger MR in the Ba-doped samples compared with the prototype Sr_2FeMoO_6 is associated with the lower saturation field. The optimization of T_C and MR in (Sr_(1.6)Ba_(0.4))FeMoO_6 other than in the reported (Sr_(0.4)Ba_(1.6))FeMoO_6 can be understood according to the two competing effects: anti-site defects and chemical pressure.