Modification of the domain kinetics in congruent lithium niobate by proton exchanged surface layers

We have studied the domain kinetics in congruent lithium niobate (CLN) single crystals with different types of the proton exchanged surface layers. The influence of the artificial dielectric layers and the surface gradient of the spontaneous polarization on the domain structure geometry, the shape of the individual domains, and the switching parameters were demonstrated. It was shown that after several cycles of polarization reversal the domain kinetics changes drastically. As a result the domain geometry is defined by spatial distribution of the residual domains existing in the area of domain merging during the previous switching. The role of residual domains increases with the cycle number