Polarization reversal process in K₂ZnCl₄ studied by the nematic liquid crystal technique

Abstract

The nematic liquid crystal technique has been applied to the study of the polarization reversal process in the commensurate-ferroelectric phase of K₂ZnCl₄ where there are six types of domains distinguished by the phase of the order parameter ψ = n π/3 (n = 1, 2,…, 6). A single domain crystal undergoes polarization reversal through the sidewise expansion of domains nucleated at the predetermined locations in the bulk or at the crystal edges. The phase of the primary order parameters differs by φ between the switched and unswitched regions. In addition we found that domain walls serve as sources to create DCs in the commensurate-to-incommensurate transition.