An electro-mechanically coupled phase field model for domain evolution in ferroelectric materials is presented. The inner length scale introduced by the model gives rise to size effects, especially in the context of thin films and nanodots. Such size effects are investigated by numerical simulations regarding the poling behavior of electroded barium titanate thin films and domain evolution in ferroelectric nanodots.

Keywords: Phase field, Ferroelectrics, Ginzburg-Landau equation, Thin films.