Ferroelectric domain switching in rhombohedral-phase PLZT ceramics

Rhombohedral-phase PLZT ceramics can be made with a degree of transparency useful for electrooptic device applications. In addition to this transparency, there are several other significant characteristics: (1) intrinsic memory associated with the ferroelectric state, (2) changeable birefringence dependent upon remanent polarization, and (3) the capability of having remanent polarization switched at room temperature by moderate fields (∼ 10 kV/cm).This paper reports on the switching behavior of rhombohedral-phase PLZT ceramics under a variety of conditions that involve various combinations of electric fields, strain fields, and mechanical clamping. The experiments described in this paper demonstrate that under ordinary conditions, polarization reversal involves both 180° and less-than-180° domain switching and that the birefringence changes useful for electrooptic device applications depend critically on the extent to which less-than-180° domain switching takes place. Included in this paper are results on device structures and experimental techniques developed to enhance the birefringence changes achieved when the ceramic is used in electrooptic devices.