Effect of the Ru content on the phase equilibria in the RuSr₂GdCu₂O₈ synthesis

In this study we report the synthesis and characterization of four samples prepared with a nominal RuSr₂GdCu₂O₈ starting composition following a two-step procedure, involving the Sr₂GdRuO₆ compound as precursor, in a controlled atmosphere. A chemicalvapour-transport process in an open system is used to control the Ru content in these samples during the annealing cycle. We observe that high Ru-oxides mass transport results in a change of the phases in equilibrium at the RuSr₂GdCu₂O₈ composition and a multiphase product is obtained. Rietveld refinement analysis and SEM-EDX studies are carried out in order to estimate the Ru content in the asprepared RuGd1212.