Microstructure of epitaxial YbBa\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e7\u3c/sub\u3e superconducting films grown by a new liquid-gas-solidification technique

We have studied the microstructures of epitaxial YbBa2Cu3O7 superconducting films grown on SrTiO3 [100] and [110] substrates by a new liquid-gas-solidification processing technique. Films grown on SrTiO3 [100] and [110] substrates are epitaxially oriented with [001] and [110] axes normal to the film surface. Twinned domains of ~200 Å in size are observed in the [001] oriented films. Most defects observed can be attributed to the presence of stacking faults along the c axis. The presence of Cu-O bilayer defects is also observed. Rapid oxygen diffusion in the liquid phase is found to play an important role in the microstructure of the thin films