Island growth and surface topography of epitaxial Y-Ba-Cu-O thin films on MgO

High-quality epitaxial Y1B2Cu3Ox thin films (Tc,o ≥ (R18) 90 K, jc (77 K)≥ (R18)3 ×106A/cm2) were in situ grown on MgO by KrF excimer laser ablation. The combination of in situ resistance measurements, x-ray diffraction experiments, Tc measurements, scanning electron microscopy and scanning tunneling microscopy gives clear indications for an island growth on these substrates and shows growth steps and spirals at the film surface.