Melt-textured GdSr2RuCu2O8 samples: preliminary results

The superposition of strongly anisotropic magnetic and superconducting properties, expected in Gd1212 (GdSr2RuCu2O8), makes relevant the fabrication of oriented samples of macroscopic size by melt-texturing techniques. Starting from 1 cm diameter pellets we have grown top-seeded melt-textured samples using MgO seeds. X-ray diffraction analysis shows that a certain degree of orientation is present in our samples. Large oriented domains of millimetre size were observed by polarised light optical microscopy, larger domains are expected by optimisation of growth parameters and seed. Images show even a homogeneous distribution of Gd1210 precipitates with a mean size of a few micrometres. Resistivity measurements show a 12 K wide superconductive transition with Tc onset at about 40 K, optimisation of annealing treatments are expected to reduce this width