Bilateral switching of the modulated electrooptic contrast in PLZTN ceramics

Spatial distribution of ferroelectric polarization in Pb(Zr,Ti)O3 ceramics doped with lanthanum and niobium has been investigated using scanning electrooptic confocal microscopy. Measurement of the modulated electrooptic signal in presence of a sinusoidal electric field reveals ferroelectric domains at microscopic scale not accessible to conventional polarized optical imaging. Both electrooptic images and local electrooptic loops have been observed after applying a bias electric field to the ceramic samples, being initially non-ferroelectric macroscopically. Bilateral reversal of the electrooptic contrast during the poling cycle has been detected and explained taking into account non-180° switching processes in ferroelectric grains of arbitrary orientation.