HREM INVESTIGATION OF (110) ORIENTED YBA2CU3O7 THIN-FILMS DEPOSITED ON (110) SRTIO3 SUBSTRATES

The epitaxial growth and microstructure of YBa2Cu3O7 thin films on (11 0) SrTiO3 substrates was investigated by high-resolution electron micr oscopy. The single thin films and heterostructures with PrBa2Cu3O7 and SrTiO3 separating the superconductor layers were deposited by DC sput tering. All layers were grown with the [110] direction perpendicular t o the substrate surface with the c-axis of the YBa2Cu3O7 film oriented parallel to the [001] direction of the substrate. Resistance measurem ents showed that, by applying a template growth procedure, T(c) values of up to 85 K can be obtained. Stacking faults were found to be the d ominant defect type in the superconducting film. A structural model fo r a novel type of these defects inducing a local 2-3-5 cation stoichio metry was deduced by comparison between experimental and simulated hig h-resolution images. Antiphase boundaries with a habit plane close to the (110) plane of YBa2Cu3O7 were detected.