Domain stability in PZT thin films

AFM measurements were made on 111 textured lead zirconate titanate thin films excited by a 1 V-rms in the presence of various DC biasing voltages. Domain pinning sites were found in the film. All sites were located at grain boundaries and were coincident with abnormally large piezoelectric displacements in the film. Different sites were associated with domain polarization aligned toward the free surface of the film than with polarization aligned toward the substrate. Finite element calculations used to determine residual stress as a function of grain misorientation showed that large residual stresses and strains normal to the film plane would be generated at grain boundaries for certain grain misorientations. Domain pinning sites in PZT thin films are interpreted in terms of residual stresses at grain boundaries due to grain misorientation.