Direct pulse technique for spontaneous polarization dynamics and molecular reorientation processes in ferroelectric liquid crystals

Abstract

A method has been devised for studying the spontaneous polarization, dynamics of polarization reversal, and the molecular reorientation processes that occur in the bulk and surfaces of ferroelectric liquid crystals. These studies have been carried out by analyzing the current response to triangular- and square-wave forms. The current response to a triangular wave yields the spontaneous polarization by conveniently subtracting the background contribution due to the conductive and capacitive currents. Molecular reorientation processes which take place within the bulk and the boundary surface layer can be studied by the appearance of polarization current peaks on the triangular-wave response. The dynamics of polarization reversal between bistable states and of the polarization change between the zero-field relaxed state and either of the saturation remanent polarization states have been studied by applying ‘‘symmetric’’ and ‘‘asymmetric’’ square waves. The technique can also be successfully applied to solid ferroelectrics for studying the spontaneous polarization and the domain dynamics during switching.