Growth and characterization of single crystals of high T-c superconductors and related phases

In this report we present and discuss our recent results on crystal growth and characterization of high T-c superconductors and related phases. We focus on three systems: Re2CuO4 (Re-214, with Re=La and Nd), ReBa2Cu3Oy (Re-123, with Re=rear earth) and Bi-Sr-Ca-Cu-O (BiSCO). The crystals were obtained by spontaneous nucleation in slowly-cooled, non-stoichiometric melts. They were platelet-shaped, with typically mm-size dimensions in the basal plane and 10-1000 microns thickness. Resistivity characteristics as a function of temperature, structural X-ray analysis and EDX microanalysis were carried out in order to characterize the compounds. The systematic optimization of the melt composition and of the growth parameters allowed, in the most part of the experiments, to reproducibly grow good quality crystals, comparable with the best materials described in literature.