Annular dark-field image simulation of the YBa2Cu3O7-delta/BaF2 interface

Scanning transmission electron microscope (STEM) images of the interface of a YBa2Cu3O7-delta (YBCO)/Ba-2 thin film bilayer show a relatively wide ( a pproximate to 40 Angstrom) contrasting band at the interface when viewed ed ge-on. Simulation of annular dark-field (ADF) images of this interface reve al that a significant contribution to this wide band of contrast is due to strain from dislocations oriented perpendicular to the incident beam direct ion and this contrast cannot be explained using solely a Z-contrast interpr etation of ADF images. We believe that these are the first such calculation s which predict that the presence of a misfit dislocation network can contr ibute a significant amount of contrast to cross-section ADF images of an in terface. (C) 2000 Elsevier Science B.V. All rights reserved.