Ferroelectric Domain Evolution Research Articles

Domain structure and evolution in (PbMg1∕3Nb2∕3O3)0.75(PbTiO3)0.25 single crystal studied by temperature-dependent piezoresponse force microscopy

Ferroelectric domain structure and evolution in (110)-cut relaxor ferroelectric (PbMg1∕3Nb2∕3O3)0.75(PbTiO3)0.25 (PMN-25PT) single crystal have been studied by means of temperature-dependent piezoresponse force microscopy. It revealed that, during heating, the as-grown PMN-25PT single crystal exhibits a transition from a ferroelectric microdomain structure to a paraelectric phase; while after being cooled back to room temperature the microdomain structure is rebuilt. Domains with size of tens of nanometers were also observed embedded in the microdomains. By contrast, the poled sample exhibits transitions from macro- to microdomain structures at 90 °C and from microdomain structure to paraelectric phase at 115 °C. These direct observations are consistent with temperature-dependent relative permittivity measurements. In situ polarization switching of the domains was also demonstrated.

Evolution and removal of ferroelectric domains on KNbO3film by an atomic force microscope with a conductive cantilever

Evolution and removal of ferroelectric domains on KNbO₃film by an atomic force microscope with a conductive cantilever

Three-dimensional ferroelectric domain imaging of bulk Pb(Zr,Ti)O3 by atomic force microscopy

We report on the ferroelectric domain evolution as a function of the depth of the surface of 100 μm thick bulk Pb(Zr,Ti)O3 (PZT) doped with 2% Nb. Ferroelectric domain imaging (FDI) was performed by piezoelectric detection assisted by atomic force microscopy (AFM). The depth evolution of the polarization orientation was obtained by repeated surface chemical etching followed by FDI. It was observed that backswitching mainly occurred close to 90° domain and grain boundaries. The depth of these domains was estimated to be about 500 nm. This indicates that nonpenetrating domains of opposite polarity can retain their polarization vector near the surface region without the help of a top electrode interface. It also supports the idea that they act as preferential nucleation sites for polarization reversal. We suggest that AFM FDI combined with proper etching methods could be used to construct a three-dimensional image of the whole domain structure by stacking two-dimensional images layer by layer.

Eshelby tensor for piezoelectric inclusion and application to modeling of domain switching and evolution

The two-dimensional piezoelectric Eshelby tensor, which relates constrained strains and electric displacement in an elliptic inclusion to specified uniform eigenstrains and eigenelectric displacement therein, is obtained in closed form by using the extended Lekhnitskii’s formalism. The symmetric property of piezoelectric Eshelby tensor is also established. The Eshelby tensor is then used to derive the free energy expression due to the introduction of an elliptic crystallite into a poled ferroelectric matrix. By examining the change of potential energy before and after polarization switching of the crystallite, a domain switching criterion which considers both the interaction of applied electroelastic field with switching strains and switching polarization and the change of electroelastic properties of switched domain is proposed. The derived free energy solution is also applied to study the evolution of 180° and 90° domain nuclei in ferroelectric crystals and the effects of material anisotropy and electromechanical coupling on ferroelectric domain evolution are examined.

In situobservation of the ferroelectric-paraelectric phase transition in a triglycine sulfate single crystal by variable-temperature electrostatic force microscopy

The ferroelectric-paraelectric phase transition of triglycine sulfate single crystal was investigated by variable-temperature electrostatic force microscopy. Near the Curie temperature ${T}_{C},$ the evolution of ferroelectric domains with temperature was observed in situ. We have found that the domain structures are not thermally reversible until ${T}_{C}\ensuremath{-}2\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}lTl{T}_{C},$ within which the domain density N diverges reversibly via ${(T}_{C}\ensuremath{-}{T)}^{\ensuremath{-}\ensuremath{\eta}},$ with $\ensuremath{\eta}=0.54\ifmmode\pm\else\textpm\fi{}0.05,$ larger than is predicted by mean-field theory. The spontaneous polarization P in individual domains decreases continuously and reversibly to zero and eventually vanishes at ${T}_{C}.$ Quantitative analysis reveals that ${P}^{2}\ensuremath{\propto}{(T}_{C}\ensuremath{-}T).$

Three‐Dimensional Computer Simulation of Ferroelectric Domain Formation

Three‐dimensional (3‐D) computer simulations of ferroelectric domain formation and evolution were performed, using a computer simulation model based on the time‐dependent Ginsburg‐Landau equations. A cubic‐to‐tetragonal ferroelectric phase transition is considered. It is shown that the initial stage of the transition during the annealing of a quenched cubic paraelectric phase involves the nucleation and growth of the ferroelectric domains, followed by the domain coarsening leading to the formation of 90° and 180° domain structures. Part of the 3‐D results reported here confirm our conclusions made earlier for the two‐dimensional (2‐D) case, namely, the nonlocal elastic interactions are critical to the formation of twin structure and the dipole‐dipole interactions are responsible for the head‐to‐tail arrangements of dipoles at twin boundaries. In contrast to our previous work, and others; the effect of the depolarization energy was explicitly incorporated into the simulation model. It is found that when there are no surface charges to compensate the Lorentz field due to the polarization charges, and if the system is mechanically clamped, both 90° and 180° domains are thermodynamically stable.

Nonlinear evolution of ferroelectric domains

The nonlinear evolution of ferroelectric domains is investigated in the paper and a model is proposed which can be applied to numerical computation. Numerical results show that the model can accurately predict some nonlinear behavior and consist with those experimental results.

Economical on-line image processing of synchrotron x-radiation topographs

The modestly priced INTELLECT 100 image processing system has been used to enhance white radiation topographs taken with the TV detector at the X-ray topography station at the Daresbury SRS. A very substantial reduction in noise with a corresponding dramatic improvement in image quality was obtained by gamma variation and integration times of less than 0.5s. This compromise enabled many dynamic processes to be followed, effectively in real time with low noise. With such a processor, the spatial resolution of the system was measured to be 17±2 μm. Examples of the evolution of magnetic and ferroelectric domains in applied fields are presented. Changes in micostructure associated with the phase transition in DKDP are briefly described.

Evolution of ferroelectric domains in TGS single crystals

The reshaping of ferroelectric domains in TGS, after a heat treatment, is investigated when the crystal is surrounded either by an insulating medium or a conductive one (mercury, vapour-deposited gold, or silver paste electrodes). The rates of evolution of the domain structure are compared. The results lead to the assumption that, in the last case, the crystal is separated from the electrodes by non-ferroelectric surface layers. L'étude de l'évolution des domaines ferroélectriques dans le TGS a été effectuée, lorsque le cristal se trouve soit dans un milieu isolant, soit dans un milieu conducteur (mercure, électrodes d'or évaporées sous vide, ou peintes à la laque d'argent). Nous avons comparé les vitesses d'évolution des domaines dans les deux cas. Les résultats obtenus nous ont conduit à supposer que, dans le cas d'un milieu conducteur, il existe, entre le cristal et les électrodes, des couches de surface non ferroélectriques.