Domain wall motion in epitaxial Pb(Zr,Ti)O3 capacitors investigated by   modified piezoresponse force microscopy
  We investigated the time-dependent domain wall motion of epitaxial PbZr0.2Ti0.8O3 capacitors 100 nm-thick using modified piezoresponse force microscopy (PFM). We obtained successive domain evolution images reliably by combining the PFM with switching current measurements. We observed that domain wall speed (v) decreases with increases in domain size. We also observed that the average value of v, obtained under applied electric field (Eapp),showed creep behavior: i.e. <v> ~ exp(-E0/Eapp)^$\mu$ with an exponent $\mu$ of 0.9 $\pm$ 0.1 and an activation field E0 of about 700 kV/cm. 
S. M. Yang, J. Y. Jo, D. J. Kim, H. Sung, T. W. Noh, H. N. Lee, J.-G.   Yoon, and T. K. Song