On the simulation of the hysteresis loop of polycrystalline PZT thin films

We investigate experimentally and numerically the polarization hysteresis loop of a PZT thin film utilized in MEMS actuators. A fully coupled electromechanical phase-field technique is employed for the numerical prediction part, starting from a simplified model of the thin film proposed on the basis of several experimental evidences. It is shown that polycrystalline nature of the film plays a fundamental role. In particular the simulations demonstrate that grains with dielectric interfaces and stochastic orientation of the crystallographic directions have a significant impact on the overall hysteresis loop. (paper)