From glissile to sessile: Effect of temperature on 〈110〉 dislocations in perovskite materials

Abstract

In perovskite-type strontium titanate (SrTiO3) 〈110〉 dislocations, which are the main carriers of plastic flow at low temperature, lose their mobility as temperature increases, leading to brittle failure above 1050 K. We present theoretical evidence for a change in their core structure into a sessile, climb-dissociated configuration at high temperature. This mechanism is shown to operate in both SrTiO3 and MgSiO3, indicating that it may be a general feature of perovskite-type materials. It follows that the activity of the 〈110〉 slip system depends critically on the strain rate-temperature couple, ε̇T.