Epitaxial films of `BSCCO´ grown from liquid KCl solutions onto several substrates

A liquid-phase epitaxy growth technique (LPE) was used to obtain truly epitaxial BSCCO films on SrTiO₃ and LaGaO₃ substrates. Single-phase samples of the 2201 and of the 2212 phase have been grown. 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 a mirror-like surface, small mosaic spread, and thicknesses of 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 correspondence with twinning domain boundaries of the LaGaO₃ substrates