Driving forces on domain walls in ferroelectric materials and interaction with defects

The driving force on a domain wall in a piezoelectric material is identified by using a variational principle. In addition to the domain wall, point defects are considered. These defects are modeled as electrically charged centers of dilatation (or contraction). For representative numerical simulations, the finite element method (FEM) is used. The simulations allow the analysis of the interaction of point defects and domain walls. It is found that point defects have the ability to reduce the driving force on the domain wall. This can potentially lead to the hindering of the domain wall mobility which is suspected to be a mechanism in electric fatigue.