Figure 2
From: Giant Dielectric Permittivity in Ferroelectric Thin Films: Domain Wall Ping Pong

The closed and open symbols show the switching current density as a function of the inverse coercive field of the PZT in capacitors with different sizes for the forward expansion and sideways wall motion of the nucleating domains, respectively.
The data can be fitted by a red solid line, according to Merz’s law. The black solid line shows the domain expansion time as a function of the current density for the nucleating domains to touch the opposite electrode.