Synthesis effects on the magnetic and superconducting properties of RuSr2GdCu2O8

A systematic study on the synthesis of the Ru-1212 compound by preparing a series of samples that were annealed at increasing temperatures and then quenched has been performed. It results that the optimal temperature for the annealing lies around 1060-1065 degreesC; a further temperature increase worsens the phase formation. Structural order is very important and the subsequent grinding and annealing improves it. Even if from the structural point of view the samples appear substantially similar, the physical characterizations highlight great differences both in electrical and magnetic properties related to intrinsic properties of the phase as well as to the connection between the grains as inferred from the resistive and the Curie-Weiss behaviour at high temperature as well as in the visibility of field cooled and zero field cooled magnetic signals.