Shur, V., Shishkin, E., Baturin, I., Chernykh, A., Kuznetsov, D., Lobov, A., Shur, A., Dolbilov, M. and Gallo, K.
Field induced evolution of regular and random 2D domain structures and shape of isolated domains in LiNbO3 and LiTaO3
At 11th International Meeting on Ferroelectricity.
05 Sep 2005.
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Static domain patterns produced by application of the external electric field in single crystals of congruent, stoichiometric and MgO doped lithium niobate LiNbO3 (LN) and lithium tantalate LiTaO3 (LT) were investigated experimentally. The study of the domain kinetics by computer simulation and by switching of the model structure showed applicability of the kinetic approach to explanation of the domain shape and domain structure evolution.
The step-by-step domain growth was realized during the model experiment. The evolution of two-dimensional (2D) domain patterns produced by application of external electric field using lithographic 2D electrode grating has been investigated in congruent LN. It was shown that the domain kinetics is governed by merging of individual domains and the formed macro-scale domains are similar to the ones obtained in real samples including full variety of shapes from triangles to hexagons and even concave ones. The domain shape details were easily distinguished by optical microscopy for used 10-?m-period grating.
Computer simulation using simple local switching rules proposed for step-by-step domain growth in terms of cellular automata allows us to get a good agreement with domain patterns observed experimentally by various scanning probe microscopy modes. Proposed kinetic model allows us to explain all observed domain shapes both in macro-and micro-scales. One of the main consequences of the model is that the domain shape is governed by the kinetics and strongly affected by such experiment’s conditions as electric field pulse parameters and screening properties. Original scenarios of the domain structure evolution were revealed experimentally and discussed accounting for the decisive role of the retardation of the screening process.
It was shown that the domain evolution during decay of the highly-nonequilibrium state represents a self-organizing process, in which the screening plays the role of feedback during polarization reversal. For short electric pulses the screening is ineffective and uncompensated depolarization field drastically change the domain kinetics thus producing the equidistant arranged arrays of small sub-micron domains.
The research was supported in part by INTAS (Gr.03-51-6562), by RFBR (Gr.04-02-16770), by FAE (Gr.A04-2.9-240, program DSPHE Gr.49130), by U.S. CRDF BRHE and FAE (PhD Award No.Y1-P-05-20/4146).
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