High-resolution electron microscope images were presented which showed longitudinal sections of what was essentially an edge dislocation in rutile. The core of the dislocation was apparently well delineated, allowing atomic steps along the dislocation to be resolved. The dislocation appeared to be essentially undissociated in the bulk of the crystal, whereas at the intersection of the dislocation with the crystal surface, dissociation occurred to a width of 37Å over a length of approximately 200Å. Contrast considerations suggested that there will be some advantages in imaging both edge and screw dislocations in longitudinal section. For rutile, interpretation of the image was complicated by the presence of strong image contrast effects arising from small misalignments of either the incident electron beam or, more important in the present context, small tilts of the crystal away from precise alignment parallel to the optic axis of the objective lens. A physical explanation of the observed contrast was given, which was consistent with the slip system {011}<011> for the dislocation.

Resolution of Atomic Steps on Dislocations in Rutile. Bursill, L.A., Blanchin, M.G.: Philosophical Magazine A, 1984, 49[3], 365-82