Invited:
Domain wall shape in uniaxial ferroelectrics

The variety of the domain wall orientations appeared in uniaxial ferroelectrics during polarization reversal will be presented and described. The wall orientation was considered in terms of kinetic approach based on analogy with crystal growth.

The theoretical approach predicted the domain wall orientation defined by crystal symmetry leading to convex polygonal domains, whereas the domain shape depends on the switching conditions. The step generation rate and kink motion velocity are proportional to the excess over the thresholds of the local value of the local electric field produced by applied voltage and partially screened depolarization field. The change of the wall orientation caused by retardation of the bulk screening was demonstrated. The straight walls appeared for determined step generation at fixed points and anisotropic kink motion,¹ whereas the stochastic step generation leads to curved walls.²

The determined step generation at the domain vertices stimulated formation of the convex polygonal domains with walls parallel to the main crystallographic axis which shapes match to the crystal symmetry. The screening retardation leads to wall deviation and formation of the irregular polygons and stars.² The fast restoration of the initial wall orientation after domain merging is due to appearance of the short-lived superfast domain walls.³ The measured giant velocity increase of the deviated domain walls was attributed to increase of the kink concentration.

The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University (Reg.№ 2968) which is supported by the Ministry of Science and Higher Education RF (Project № 075-15-2021-677) was used. The research was made possible by Russian Science Foundation (Project № 19-12-00210).

1 V.Ya. Shur, A.R. Akhmatkhanov, Phil. Trans. R. Soc. A., 376, 20170204 (2018).

2 V.Ya. Shur, E.V. Pelegova, M.S. Kosobokov, Ferroelectrics, 569, 251 (2020).

3 A.A. Esin, A.R. Akhmatkhanov, V.Ya. Shur, Appl. Phys. Lett. 114, 092901 (2019).