Ferroelectric microdomains and microdomain arrays recorded in strontium–barium niobate crystals in the field of atomic force microscope

摘要

Microdomains and various one-dimensional (1D)- and two-dimensional (2D)-microdomain arrays were formed under dc-voltages applied to the tip of an atomic force microscope (AFM) in ferroelectric SrxBa1-xNb2O6 crystals. Detailed studies of the characteristics of the AFM—recording and decay kinetics of the written arrays have shown that the crucial factors of the stability of a domain array are its dimensionality and discreteness (described by a distance Δ between the recorded point domains forming the array). The dependence of the stability on the discreteness of domain ensembles is analyzed. With decreasing Δ, the decay times of the domain ensembles increases. The stability of 2D arrays (domain squares, complex-shaped arrays composed of the domain ensembles of opposite polarity) by orders of magnitude exceeds that of 1D-arrays (domain chains and lines) provided all factors of recording being the same. As an illustration, the decay time of individual (spatially separated) domains and quasicontinuous domain lines are tens of minutes and about 20 h, respectively, whereas a quasicontionuous domain square persists within at least ten days. We assume the existence of cooperative interactions in microdomain ensembles, which reveal themselves even in arrays consisting of spatially separated point domain.