Characterization of PZT films by scanning force microscopy (SFM)

Scanning Force Microscopy (SFM) has been used for the determination of friction, phase transformation, piezoelectric behavior (contact mode), polarization state and dielectric constant (non contact mode) in several nanometer regions of Lead Zirconate Titanate (PZT) films. The use of the SFM tip, in the contact mode, to polarize different nanoregions of the film and to apply an oscillating field thereon, led to effective piezoelectric coefficients and piezoelectric loops. In the non-contact mode, application of an ac signal (frequency ω) to the tip-electrode system produced an oscillation of the tip at ω (fundamental or first harmonic) and 2ω (second harmonic). The signals ω and 2ω were related to the state of polarization and the dielectric constant of the film. Analysis of the combined contact, non-contact and friction force microscopic data have provided considerable insight into the piezoelectricity and polarization in the nanodomains.