Phase field modeling of domain structures in ferroelectric materials

A phase field model based on the work of Hu and Chen has been computationally implemented. The approach uses a minimization of global free energy to simulate the evolution of domain structures through the time dependent Ginzburg-Landau equation. The work focuses on the assumptions made when setting up the free energy function and the effect of these assumptions on the behavior of the model. Polarization is used as the independent variable. A fourth order polynomial is used to create four energy minima that represent the tetragonal phase in the two-dimension simulations. Linear superposition is used to modify the energy to account for the effects of sterss, electric field, and polarization gradients. This approach neglects field concentrations associated with material anisotropy and local geometric features. Considerable work will be required to incorporate these effects.