Magnetism of the double perovskite Sr2FeMoO6

Abstract We have completed a systematic study of the magnetization of a single crystal of double perovskite Sr 2 FeMoO 6 over a wide range of temperatures and fields. Near the ordering temperature of 405.0 K, the magnetization is described by critical exponents β =0.50±0.03 and γ =1.20±0.03. At low temperature, the compound is ferromagnetic, but the moment corresponds to only 3.3 μ B /formula unit, significantly less than the 3.6 expected. We discuss these observations in terms of mis-site defects of the Fe and Mo ions.