Coexistence of Superconductivity and Magnetism in Ruthenocuprates

The layered ruthenocuprate materials RuSr2LnCu2O8 and RuSr2(Ln1+xCe1-x)Cu2O10, with Ln=lanthanide or Y for both structures, consist of pairs of CuO2 planes alternating with perovskite-like sheets of vertex sharing RuO6 octahedra. Samples of Ru-1212 and Ru-1222 materials were known to show both superconducting and magnetic transitions. Here, we discuss the problem of the coexistence, considering a model which includes two types of carriers responsible separately for the ordered phases. By considering the interplay between a hybridization mechanism and the direct exchange coupling between these carriers, we look at the stability of the coexisting phase assuming an inhomogeneous superconducting phase.