Observations of polarization switching processes in ferroelectric Pb(Zr,Ti)O{sub}3 thin films using piezoresponse scanning force microscopy

摘要

Polarization switching processes in epitaxial Pb (Zr,Ti)O{sub}3 (PZT) thin films grown on SrRuO{sub}3/SrTiO{sub}3 (100) were observed using piezoresponse scanning force microscopy (PFM). PFM observations were carried out directly on the PZT surface and with and on Pt top electrodes. XRD patterns exhibited that PZT thin film had only 180°domains because of a tetragonal structure and completely (001)-orientation. From PFM observations directly on PZT film, it was found that domain wall velocity in the vertical direction was estimated 89m/s. PFM observations with and on the top electrode revealed that the polarization switching processes were dependent on the switching pulse voltage. At lower switching pulse voltage regions (～1.5V{sub}c), the polarization switching occurred from only the latent nuclei. On the other hand, at higher switching pulse voltage (>2V{sub}c), the new nucleations during switching period were observed.