Phase field simulation of domain structures in ferroelectric materials within the context of inhomogeneity evolution

A phase field model for simulating the domain structures in ferroelectric materials is proposed. It takes mechanical and electric fields into account, thus allowing for switching processes due to mechanical and/or electrical loads. The central idea of the model is to take the spontaneous polarisation as an order parameter and to provide an evolution law for this parameter. The concept of evolving inhomogeneities (configuratioanl forces) can be used in this context, as the spatial distribution of the spontaneous polarisation describes the inhomogeneity of the system. The evolution is found to be in agreement with the second law of thermodynamics and to resemble the (classical) Ginzburg-Landau equation. Numerical simulations show the features of the model and the interaction of domain structures with defects.