Dislocations in plastically deformed SrTiO3

Bright-field and weak-beam TEM investigations were performed on plastically deformed SrTiO3. A gradual change from a⟨110⟩ edge-type to screw-type dislocations is found with decreasing temperature. It was found that edge dislocations undergo climb at high temperatures. In order to explain this plastic behaviour, a model is presented which is based on the temperature dependence of the dislocation core structures. At elevated temperatures edge dislocations dissociate by climb. This is impeded at low temperatures because of the lack of thermal activation. At low temperatures screw dislocations are assumed to become sessile, probably due to a non-planar dissociation of the dislocation core.