Coexistence of long-ranged magnetic order and superconductivity in the pnictide superconductor SmFeAsO(1-x)F(x) (x=0, 0.15)

Powder neutron-diffraction measurements on both SmFeAsO and the fluorine-doped superconductor, SmFeAsO0.85F0.15, show that the Sm sublattice orders magnetically. In both cases we observe a simple layered antiferromagnetic arrangement of the 0.5B Sm moments. This provides direct evidence that long-ranged magnetic order of the samarium moments coexists with superconductivity in the SmFeAsO1-xFx system.