Depolarizing-field-mediated 180° switching in ferroelectric thin films with 90° domains

Switching of the out-of-plane and in-plane polarizations in polydomain epitaxial PbZr0.2Ti0.8O3 thin films is studied using three-dimensional piezoresponse force microscopy (PFM). It is found that, under an electric field induced between the PFM tip and the bottom electrode, the 180degrees switching occurs in both c and a domains. After the removal of this field, the spontaneous reversal of the out-of-plane and in-plane polarizations back to the initial orientations takes place, evolving via heterogeneous development of antiparallel 180degrees domains. The switching of in-plane polarization inside a domains and the preferential formation of reversed 180degrees domains at 90degrees domain walls are explained by the effects of the depolarizing fields caused by transient polarization charges appearing on these domain walls. (C) 2002 American Institute of Physics.