  We show experimental switching data on microscale capacitors of
lead-zirconate-titanate (PZT), which reveal time-resolved domain behavior
during switching on a 100-ns scale. For small circular capacitors, an
unswitched domain remains in the center while complete switching is observed in
square capacitors. The observed effect is attributed to the formation of vortex
domain during polarization switching in circular capacitors. This dynamical
behavior is modeled using the Landau-Liftshitz-Gilbert equations and found to
be in detailed agreement with experiment. This simulation implies rotational
motion of polarization in the xy-plane, a Heisenberg-like result supported by
the recent model of Naumov and Fu [Phys. Rev. Lett. 98, 077603 (2007)],
although not directly measurable by the present quasi-static measurements.
