Investigation of domain switching and retention in oriented PbZr0.3Ti0.7O3 thin film by scanning force microscopy

The polarization switching and retention in oriented tetragonal lead zirconate titanate films have been investigated by piezoresponse scanning force microscopy (SFM) on the nanoscale level. We observed the processes of polarization switching by choosing suitable poling conditions. It was found that the domain nucleated from the surface under the applied field and grew via both forward and sideways growth. This switching process was different from the conventional model in which sideways growth occurs after the forward growth reaches the opposite surface. Successive sideways and forward growth was observed with the stimulation of the applied field. We also studied the retention behavior of a single domain with a diameter of about 270 nm. Simultaneous forward and sideways backswitching of polarization led to the lowering of the piezoresponse of the retained domain together with the decrease of the domain area. The temporal dependence of the retained domain area was found to fit the stretched exponential law. This study demonstrates that the SFM technique is a powerful tool providing insight into the complicated behaviors of ferroelectric domains.