Domain Wall Creep in Epitaxial Ferroelectric Pb(Zr0.2Ti0.8)O3 Thin Films

Abstract

Ferroelectric switching and nanoscale domain dynamics were investigated using atomic force microscopy on monocrystalline $\mathrm{P}\mathrm{b}\mathrm{(}\mathrm{Z}{\mathrm{r}}_{\mathrm{0.2}}\mathrm{T}{\mathrm{i}}_{\mathrm{0.8}}\mathrm{)}{\mathrm{O}}_{\mathrm{3}}$ thin films. Measurements of domain size versus writing time reveal a two-step domain growth mechanism, in which initial nucleation is followed by radial domain wall motion perpendicular to the polarization direction. The electric field dependence of the domain wall velocity demonstrates that domain wall motion in ferroelectric thin films is a creep process, with the critical exponent $\mu$ close to 1. The dimensionality of the films suggests that disorder is at the origin of the observed creep behavior.