H2/N2 mixture atmosphere effects on the behavior of the double perovskite compound Sr2CoMoO6

Sr2CoMoO6 and Sr2CoMoO6-delta ceramics have been obtained by solid state reaction in air and in a H-2/N-2 gas mixture. At room temperature, as shown by X-ray diffraction, both compounds have a tetragonal perovskite-like structure with doublet unit-cell parameters, space group I4/m, with a=5.5575, c=7.9342 in Sr2CoMoO6 and a=5.5683 and c=7.9395 in Sr2CoMoO0.95. The latter contains small traces of Co and SrCoO2.61, with an almost expansion. The magnetic susceptibility indicates that Sr2CoMoO6 is an antiferromagnet with T-N=37 K. The magnetization was found to be the same in both samples, while the electric properties, originating from the oxygen content, are drastically affected.