EPITAXIAL-FILMS OF BSCCO GROWN FROM LIQUID KCL SOLUTIONS ONTO SEVERAL SUBSTRATES

Using liquid phase epitaxy growth technique (LPE) we have obtained truly epitaxial BSCCO films on SrTiO3 and LaGaO3 substrates. Single-phase samples have been grown both of the 2201 and of the 2212 phase. The growth liquid is a saturated solution of the BSCCO constituent oxides in KCl, and a suitable thermal gradient allows chemical transport from the solute to the substrate. The films have mirror-like surface, small mosaic spread and thickness up to a few microns. The as-grown samples are fully superconducting. The typical resistance vs temperature curve shows a metallic behavior down to about 80 K, followed by a narrow superconducting transition, with zero resistance reached at about 75 K. The transport properties of the films have been investigated, and found to be heavily dependent on the substrate chosen: in particular, films grown on LaGaO3 have much higher resistivities and much lower critical currents than those grown on SrTiO3 substrates. These differences are shown to be due to the presence of weak links occurring in correspondance with twinning domain boundaries of the LaGaO3 substrates.