Dislocations in paratellurite TeO2 : elastic energies and plastic deformation

2014 Paratellurite TeO2 is a crystal with exceptional anisotropic elasticity. This is the origin of interesting acousto-optical applications; as they depend on crystalline perfection, dislocations are of particular importance and their properties are also directly linked to elasticity. We have calculated the energy of dislocations with [100], [110] and [001] Burgers vectors : in some cases, it is maximum for screw character, instead of minimum for an isotropic medium. Constant strain rate compressions have been performed to induce dislocation glide; the stress was applied along [110], [221], [100] and [001]. TeO2 crystals were brittle below 400 °C (0.7 melting temperature). Macroscopic observations (optical microscopy, X ray topography) could only give information about slip planes : { 100}, (001), {110} and { 101} seem to be activated. The existence of 010> and 110> Burger’s vectors is suggested. Tome 21 ? 5 MAI 1986 Revue Phys. Appl. 21 (1986) 289-298 MAI 1986,