Direct observation of domain kinetics in rhombohedral PMN-28PT single crystals during polarization reversal

Relaxor-based ferroelectric crystals of lead magnesium niobate-lead titanate (PMN-PT) are attracting great attention due to their prominent piezoelectric properties. Moreover, an enhancement of the integral properties requires the deep understanding of domain kinetics and domain structure evolution for application of the domain engineering techniques in relaxor-PT materials. Here, we demonstrate the results of studying the domain structure evolution by direct optical imaging during polarization reversal in [111]-oriented rhombohedral PMN-PT single crystals. Three domain types involved in the switching process have been revealed. The following consequent stages of the domain structure evolution have been separated: (I) nucleation and growth of a up arrow-domains and 2a-CDW and (II) nucleation and growth of c down arrow-domains. The undesirable effect of the partial backswitching during the electric field decrease was attributed to the clamped switching conditions.