The first results of transmission electron microscopic observations of LiNbO3 plastically deformed at above 0.8Tm were reported. The stress orientation was chosen so as to activate simple and double {1¯1•2}<¯11•1> pyramidal glide. Rather low dislocation densities (107/cm2) were observed in the foils and, over a wide region, pinching-off of dipoles was noted. The Burgers vectors identified were compatible with the macroscopically observed glide directions. Dissociation according to the reaction,

1/3<0¯1•1>  1/18<¯2¯2•3> + 1/18<2¯4•3>

were observed. Hence the associated stacking fault was rather narrow, and the dissociation preserved the integrity of the oxygen sub-lattice. The corresponding fault energy was about 120mJ/m2.

TEM Observation of Plastically Induced Dislocations in Lithium Niobate LiNbO3 Single Crystals. A.Péter, E.Fries, J.P.Rivière: Physica Status Solidi A, 1991, 128[1], 45-53