The microstructure of YBa2Cu3O7-delta films and yttria stabilised zirconiabuffer layers deposited on inclined hastelloy substrates

YBa2Cu3O7-delta films have been grown on polycrystalline metallic substrate s using intermediate yttria stabilised zirconia (YSZ) buffer layers. The bu ffer layers were grown by pulsed laser deposition using the inclined substr ate deposition technique, whereby the substrate is tilted so that the ablat ed species arrive under an oblique incidence angle. One of the consequences of the inclined geometry is the alignment of the buffer layer crystal grai ns within the plane of the film which enables the subsequent deposition of YBa2Cu3O7-delta films With J(c)'s of up to 10(5) A/cm(2). We present result s showing that the optimum substrate inclination angle for the YSZ buffer l ayer deposition is around 55 degrees, and that the in-plane alignment impro ves linearly with film thickness. We also show transmission electron microg raphs which demonstrate that grain sizes get larger and appear to be better aligned towards the buffer layer surface. We use these results to propose a mechanism by which texture occurs during inclined substrate deposition. T he mechanism is based on three requirements inferred from our microstructur al data: columnar growth, tilting of grains towards the incoming ablated sp ecies, and a preferred growth orientation normal to the substrate surface.