MICROSTRUCTURE OF (001), (110) AND (103) ORIENTED THIN-FILMS OF YBA2CU3O7-X INVESTIGATED WITH STM, SEM AND HRTEM

Epitaxial films of (110) or (103) YBa2Cu3O7-x grown on (110) SrTiO3 su bstrates by laser ablation are compared to (001) films. Their microstr ucture is investigated with scanning tunneling microscopy, scanning el ectron microscopy and high-resolution transmission electron microscopy . The growth of steps, terraces and spirals originating from screw dis locations commonly seen in c-axis films is inhibited in films grown on (110) SrTiO3. In the case of (103) oriented films, the growth of 90-d egrees twisted domains produces a tooth-like structure with preferred orientation. The influence of vicinal substrates (a few degrees of mis orientation) on the film growth, on the nature of defects and on the r esistive behavior is also investigated.