Nanoscale imaging of domain dynamics and retention in ferroelectric thin films

We report results on the direct observation of the microscopic origins of backswitching in ferroelectric thin films. The piezoelectric response generated in the film by a biased atomic force microscope tip was used to obtain static and dynamic piezoelectric images of individual grains in a polycrystalline material. We demonstrate that polarization reversal occurs under no external field ~i.e., loss of remanent polarization! via a dispersive continuous-time random walk process, identified by a stretched exponential decay of the remanent polarization. © 1997 American Institute of Physics. @S0003-6951~97!00550-0#