Growth mechanism of YBa<inf>2</inf>Cu<inf>3</inf>O<inf>7-δ</inf> thin films on vicinal MgO

YBa2Cu3O7-δ thin films have been grown on vicinal MgO substrates by pulsed-laser ablation. The substrate topography has been shown to affect the microstructure of the film. The step edge act as preferential sites for island nucleation, controlling the in-plane alignment of the islands. The resulting microstructure consists of c-axis oriented grains which have a large aspect ratio. The formation of a well-defined substrate surface enables the growth of highly oriented YBa2Cu3O7-δ films, on a substrate where there is a large lattice mismatch. The films have been characterized by both X-ray diffraction techniques and transmission electron microscopy. © 1991.