Magnetic properties of the double perovskites A2FeMoO6; A = Ca, Sr, Ba

Abstract
The double-perovskite oxides Ca2FeMoO6, Sr2FeMoO6 and Ba2FeMoO6 show evidence of ferromagnetic metallic behaviour, with Curie temperatures of 345-426 K and saturation magnetization of 3.5-3.9 µB/formula unit. Ceramics show little anisotropic magnetoresistance, but the low-field isotropic negative magnetoresistance of Sr2FeMoO6 is 7% in 1 T at room temperature and reaches 15% at 77 K. An effect of about 1% is found in 20 mT at room temperature in both ceramics and pressed powders of this compound.