Fatigue effect in ferroelectric crystals: Growth of the frozen domains

The model of the fatigue effect during cyclic switching caused by growth of the frozen domain area with charged domain walls has been proposed. It was claimed on the basis of the previous experimental results that for switching in increasing field the frozen domain area started to grow at the given sub-threshold field value and stopped at the threshold field. The influence of the shape and frequency of the field pulses used for cyclic switching has been considered. The uniaxial ferroelectric stoichiometric lithium tantalate single crystals produced by vapor transport equilibration with record low value of coercive field have been chosen as a model material for experimental verification of the model. The formation of the charged domain walls as a result of cyclic switching has been revealed by analysis of the domain images obtained by optical and Raman confocal microscopy. It has been shown that the fatigue degree is equal to the fraction of the frozen domain area. The experimental dependence of the switched charge on the cycle number has been successfully fitted by modified Kolmogorov-Avrami formula. The experimentally observed frequency independence of fatigue profile for rectangular pulses and frequency dependence for triangular pulses has been explained by proposed model. © 2012 American Institute of Physics

Polarization reversal and jump-like domain wall motion in stoichiometric LiTaO 3 produced by vapor transport equilibration

The polarization reversal and domain structure evolution has been studied in stoichiometric lithium tantalate prepared by vapor transport equilibration process. The first in situ visualization of domain kinetics has demonstrated the jump-like motion of few strictly oriented plane domain walls, which leads to short isolated current pulses in the switching current data. The proposed model of jump-like domain wall motion caused by interaction with pinning centers representing the areas with increased value of the threshold field is based on the effect of retardation of bulk screening. The derived formulas were applied successfully for analysis of the field dependence of the total switching time. The durations of wall jumps and wall stays (rest times) extracted from the switching current data are analyzed separately. The deceleration of the wall motion velocity during jump is controlled by the trail of residual depolarization field produced by bound charges and screening charges in the area behind the wall. The duration of the rest time is governed by the bulk screening of residual depolarization field. The value of Hurst exponent 0.75 obtained by fractal analysis of the switching current data has confirmed the essential influence of prehistory on the domain wall motion. The measurements of the coercive field by switching in bipolar triangular pulses in wide range of the field ramp rate have allowed us to extract the record low value of coercive field 60 V/mm for quasi-static polarization reversal. © 2012 American Institute of Physics

Domain shape instabilities and dendrite domain growth in uniaxial ferroelectrics

The effects of domain wall shape instabilities and the formation of nanodomains in front of moving walls obtained in various uniaxial ferroelectrics are discussed. Special attention is paid to the formation of self-assembled nanoscale and dendrite domain structures under highly non-equilibrium switching conditions. All obtained results are considered in the framework of the unified kinetic approach to domain structure evolution based on the analogy with first-order phase transformation. This article is part of the theme issue ‘From atomistic interfaces to dendritic patterns’. © 2018 The Author(s) Published by the Royal Society. All rights reserved.14-12-00826Data accessibility. This article has no additional data. Authors’ contributions. V.Ya.S. and A.R.A. wrote this in a joint effort. Competing interests. We declare we have no competing interests. Funding. The authors acknowledge support by the Russian Scientific Foundation (grant no. 14-12-00826). Acknowledgements. It is a pleasure to acknowledge the helpful discussions with A.L. Korzhenevskii and E.L. Rumyantsev. The equipment of the Ural Center for Shared Use ‘Modern nanotechnology’ UrFU was used

Dielectric Permittivity Enhancement By Charged Domain Walls Formation In Stoichiometric Lithium Niobate

We present an experimental study of contribution of charged domain walls into dielectric permittivity of lithium niobate. It has been shown that formation of dense structure with spike-like domains leads to order of magnitude increase of permittivity, which gradually decreases with time. The decrease rate accelerates under DC bias. Dielectric permittivity decreases linearly with a logarithm of frequency. The obtained results were explained considering vibration of the steps on the charged domain walls

Formation of the charged domain walls in lithium niobate single crystals with various electrode types

The research was funded by RFBR (grant № 18-32-00641). The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University was used

Control of charged domain wall parameters in lithium niobate single crystals using various liquid and solid electrodes

The research was funded by RFBR (grant № 18-32-00641). The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University was used

Tilt control of the charged domain walls in lithium niobate

The utilization of charged domain walls (CDWs) as nanoelectronic devices requires three technological aspects to be developed: (1) controllable CDW creation, (2) tuning of CDW geometry, and (3) CDW removal. We have studied CDW formation in lithium niobate single crystals during polarization reversal using liquid and solid-state electrodes, as well as their combination. It was shown that CDW can be formed by two alternative procedures: (1) by forward switching for the liquid electrode at the Z+ polar surface and solid at the Z-one, (2) by backward switching for solid at the Z+ polar surface and liquid at the Z-one. The created CDW can be transformed to an almost neutral domain wall by the application of the field pulse of the reverse polarity for both procedures. As a result, the tilt of the formed CDW can be tuned reversibly in the range from 0.2° to 1.2° resulting in a change between isolated and highly conductive states. We have demonstrated that the created CDW can be used as a nanoelectronic channel for local electrolysis opening the additional possibilities for ferroelectric lithography. © 2019 Author(s)

Light diffraction on periodically poled domain structures in lithium niobate crystal in an sunusoidal voltage

This study was carried out with the financial support of Ministry of Education and Science of Russia (within the task No. 3.1110.2017/4.6 of the project part) and RFBR (Grant 16-29-14046-ofi_m). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU has been used

Shape of isolated domains in lithium tantalate single crystals at elevated temperatures

The shape of isolated domains has been investigated in congruent lithium tantalate (CLT) single crystals at elevated temperatures and analyzed in terms of kinetic approach. The obtained temperature dependence of the growing domain shape in CLT including circular shape at temperatures above 190 °C has been attributed to increase of relative input of isotropic ionic conductivity. The observed nonstop wall motion and independent domain growth after merging in CLT as opposed to stoichiometric lithium tantalate have been attributed to difference in wall orientation. The computer simulation has confirmed applicability of the kinetic approach to the domain shape explanation. © 2013 AIP Publishing LLC