Switching processes of thin ferroelectric films

The influence of size effects on dielectric and switching characteristics of lead titanate and lead zirconate titanate thin films with various thicknesses was studied. It was shown that with decreasing the film thickness the creep regime of domain wall movement is expanded due to shortening area where the sliding motion of domain walls occurs. In weak electric fields a deviation from the strictly exponential dependence of domain wall velocity V on the strength of an applied electric field was established with the appearance of an exponent in dependence V similar to exp[-C/E-mu], where C - constant and mu - dynamic factor. For lower thicknesses of films with polycrystalline structure the values of this factor approach to unity due to an increase of the orientation of crystallite axis. For strong fields with decreasing film thickness the domain wall mobility decreases due to an increase of near-surface defect contribution to domain wall motion. (C) 2017 Elsevier Ltd. All rights reserved.