Ferroelectric switching: a micromechanics model versus measured behaviour

The behaviour of ferroelectric polycrystals is explored using a rate-independent crystal plasticity model with self-consistent homogenisation to capture grain–grain interactions. Dimensionless parameters are introduced that allow a simple connection to be made between material constants and the nonlinear ferroelectric behaviour. In particular, combinations of material parameters are identified that cause remanent straining to be strongly suppressed. The self-consistent scheme allows for the ferroelectric response of a composite of grains with distinct sets of switching systems to be modelled. This feature is used to explore the effect of pinned domain walls and of dielectric inclusions. The model is able to reproduce the electrical response of three materials (PZT-5H, PZT-4D and Barium Titanate) under proportional stress and electric field loading, as measured in a parallel study.