Synthesis and physical properties of RuSr2GdCu2O8

The synthesis and physical characterization of single phase polycrystalline samples with composition RuSr2GdCu2O8 has been performed. We report on the electrical and magnetic measurements carried out in order to investigate and relate the properties of this compound subjected to different annealing routes. We show that while intrinsic properties as T-c and structural properties as lattice parameters remain unchanged, the physical properties are strongly affected by the final annealing in flowing Oxygen. Coexistence of superconductivity and ferromagnetism is observed in all specimens studied, while Meissner effect visibility is induced by the annealing process.