E. L. Rumyantsev

Nanoscale backswitched domain patterning in lithium niobate

We demonstrate a promising method of nanoscale domain engineering, which allows us to fabricate regular nanoscale domain patterns consisting of strictly oriented arrays of nanodomains (diameter down to 30 nm and density up to 100 μm−2) in lithium niobate. We produce submicron domain patterns through multiplication of the domain spatial frequency as compared with the electrode one. The fabrication techniques are based on controlled backswitched poling.

Formation and evolution of charged domain walls in congruent lithium niobate

We present experimental evidence of the formation of stable charged domain walls (CDWs) in congruent lithium niobate during switching. CDW evolution under the action of field pulses was in situ visualized. CDW boundary motion velocity is about 60 μm/s at 20 kV/mm. Relief of CDW strongly depends on applied field. Dielectric response in the presence of CDW demonstrates the pronounced frequency dependence in the range 50–150 °C. We propose the mechanism of CDW self-maintained propagation governed by self-consistent electrostatic interaction between the wall’s steps.

Regular Ferroelectric Domain Array in Lithium Niobate Crystals for Nonlinear Optic Applications

Abstract We present our experimental investigations of the domain evolution in lithium niobate. Particular attention is paid to the short-pitch and nanoscale domain patterning. We demonstrate the production of domain patterns with period down to 2.6 μ.m in 0.5-mm-thick LiNbO3wafers by backswitched poling using lithographic stripe electrodes and nanoscale domain patterns consisting of strictly oriented arrays of nanodomains (diameter down to 30 nm, density up to 100 μm−2).

Kinetics of ferroelectric domain structure: Retardation effects

We review the experimental and theoretical investigations of the kinetics of ferroelectric domain structure in single crystals and thin films. The significant influence of the retardation of screening process on the evolution of the domain structure is pointed out and is demonstrated in various experimental situations.

DOMAIN STRUCTURE OF LEAD GERMANATE

With the help of selective etchants as-grown domain structure arising as a result of the phase transition and its restruction in electric field is investigated in lead germanate single crystals. It is shown that this structure consists of small counter domains which are enlarged in electric field. By the use of stroboscopic lighting the domain dynamics under applied electric field is studied. It is shown that the influence of growth layers upon forward domain growth can be explained by the relative variation of the spontaneous polarization in the layers of the order of 0,1%. The observed peculiarities of sidewise motion of plane domain wall are explained by the presence of dielectric gap and by the influence of bulk screening. It is supposed that in low-field region domain wall motion occurs through the one-dimensional nucleation at the wall. Within this model it is possible to qualitatively explain the domain shape dependence on the switching conditions.

Kinetics of ferroelectric domain structure during switching: Theory and experiment

Abstract Some trends in modern research of domain kinetics during switching are reviewed. The importance of the complex investigations of model crystals by local and integral experimental methods simultaneously with computer simulation of domains evolution is stressed. Some new experimental results conserning superfast switching are presented. It is shown that the momentary domain patterns are defined by kinetics of switching process. The general theoretical approach based on nucleation theory in analogy with any phase transformations is used for explanation of all observed effects. The influence of geometrical transformations occuring during domain evolution on transient current shape is confirmed by computer simulation.

Recent achievements in domain engineering in lithium niobate and lithium tantalate

Abstract We present a survey of our recent study of the field-induced domain kinetics in single-crystalline congruent lithium niobate (LN) and lithium tantalate (LT). The proposed backswitched poling by field application to the lithographically defined metal strip electrodes allows to produce periodical micro-scale structures for nonlinear optical application and to demonstrate the first achievements in domain nano-technology.

Domain kinetics in the formation of a periodic domain structure in lithium niobate

The evolution of the domain structure in LiNbO3 with polarization switching in an electric field is investigated experimentally. Special attention is given to the formation processes of a regular domain applicable to nonlinear optical devices. A new method based on the spontaneous backswitching effect is proposed for creating a regular structure with a period of 2.6 µm in LiNbO3 with a thickness of 0.5 mm.

DYNAMICS OF DOMAIN STRUCTURE IN UNIAXIAL FERROELECTRICS

The switching of polarization in ferroelectrics is considered as the first-order phase transition. By the analogy with the theory of crystal growth it is assumed that the switching process is determined by the oversaturation degree which correspond in ferroelectrics to the magnitude of electric field on the domain boundary. It is supposed that the mechanism of domain wall motion in strong field is due to the twodimensional nucleation and in weak field is due to the one-dimensional nucleation. The criterion of strong field IS defined. From this point of view it have been explained the peculiarities of domain structure dynamics in two uniaxial ferroelectrics: lead germanate and gadolinium molybdate.

How to extract information about domain kinetics in thin ferroelectric films from switching transient current data

Abstract The paper presents the new method of mathematical treatment which allows to extract essential information about domain kinetics in polycrystal films from the traditional measurements of switching current. This information can not be obtained within the commonly used treatment. The method was verified by computer simulation and direct experiments in model single crystals.