Vortex ferroelectric domains

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 a vortex domain during polarization switching in small circular capacitors. This dynamical behavior is modeled using the Landau-Lifshitz-Gilbert equations and found to be in 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 (2007 Phys. Rev. Lett. 98 077603), although not directly measurable by the present quasi-static measurements.