Switching of ferroelectric nanostructures

Ferroelectric domain structures of epitaxial SrBi2Ta2O9 (SBT), BaBi4Ti4O15 (BBiT) and Bi4Ti3O12 (BiT) thin films as well as PZT nanostructures have been imaged at the nanometer scale. The surface polarization state was monitored using scanning force microscopy (SFM) and lock-in techniques, by measuring small vibrations of the film surface induced by a small AC voltage applied between a bottom electrode underneath the film and the SFM tip. The local ferroelectric properties were characterized by acquiring local piezoelectric hysteresis loops. The hysteresis loop measurements were interrupted at significant points and the ferroelectric domain configuration was imaged to map the switching of polarization.