An analysis which was based upon crystal symmetry and high-resolution transmission electron microscopy was proposed as a general method for identifying planar defects on the basal planes of D019 compounds. The possible (close-packing preserving) planar defects were first classified in accord with their visibility, and the magnitude of the displacement vector in prismatic projections. An analysis of experimental high-resolution transmission electron microscopic images (obtained under 2 viewing conditions), followed by the matching of simulated images, permitted an unambiguous identification. The method was applied to planar defects which were observed in D019. These were identified as being π rotations around [00•1]. It was thought that these defects had not been previously identified in D019 phases.

Identification of Planar Defects in D019 Phases using High-Resolution Transmission Electron Microscopy. P.Carvalho, B.J.Kooi, J.T.M.De Hosson: Philosophical Magazine Letters, 2001, 81[10], 697-707