Identification of epitaxial Y2O3 inclusions in sputtered YBa2Cu3O7 films: Impact on film growth

Y2O3 inclusions with typical sizes between 100 and 300 nm3, densely distributed (1016 cm−3) in sputtered YBa2Cu3O7 (YBCO) films on SrTiO3 substrates, have been identified by high‐resolution electron microscopy. The precipitates exhibit either cuboid or needlelike shapes and grow epitaxially within and on top of YBCO. The dominant orientation relationship corresponds to a situation where the two‐dimensional lattices are nearly coincident in the interfacial (001) plane. These precipitates may contribute to the generation of screw and edge dislocations. In addition, they provide a large number of potential pinning sites for magnetic flux lines, which may contribute to the observed high critical current densities.