The topography and crystallography of bicrystalline films which had been grown epitaxially onto oriented SrTiO3 bicrystals were characterized by means of scanning and transmission electron microscopy, and atomic force microscopy. The films were formed, by laser ablation, on melt-grown Σ = 13 SrTiO3 bicrystals with a misorientation of 24º around the <001> tilt axis. The transmission electron microscopic analysis revealed that the grain boundary in the film did not always faithfully follow the planar substrate grain boundary, but undulated about the average boundary plane. High-resolution electron microscopic observations of the apparently complex undulating boundary structures suggested the possibility of an overlap between differently oriented variants of the orthorhombic film. A correlation of the various images clearly indicated that an island growth mechanism was responsible for the observed grain boundary structure and morphology. It was seen that meandering of the film grain boundary was necessarily coupled to a wide range of inclinations of the grain boundary plane in the z-direction.

Characterization of Three-Dimensional Grain Boundary Topography in a YBa2Cu3O7-d Thin Film Bicrystal Grown on a SrTiO3 Substrate. J.Ayache, A.Thorel, J.Lesueur, U.Dahmen: Journal of Applied Physics, 1998, 84[9], 4921-8