Controllability of Vortex Domain Structure in Ferroelectric Nanodot: Fruitful Domain Patterns and Transformation Paths

Abstract

Ferroelectric vortex domain structure which exists in low-dimensional ferroelectrics is being intensively researched for future applications in functional nanodevices. Here we demonstrate that adjusting surface charge screening in combination with temperature can provide an efficient way to gain control of vortex domain structure in ferroelectric nanodot. Systematical simulating experiments have been conducted to reveal the stability and evolution mechanisms of domain structure in ferroelectric nanodot under various conditions, including processes of cooling-down/heating-up under different surface charge screening conditions, and increasing/decreasing surface charge screening at different temperatures. Fruitful phase diagrams as functions of surface screening and temperature are presented, together with evolution paths of various domain patterns. Calculations discover up to 25 different kinds of domain patterns and 22 typical evolution paths of phase transitions. The fruitful controllability of vortex domain structure by surface charge screening in combination with temperature should shed light on prospective nanodevice applications of low-dimensional ferroelectric nanostructures.

Structure and dielectric properties of Nd(Zn1/2Ti1/2)O3 – BaTiO3 ceramics for energy storage applications

“…It is attributed to the lower dielectric constant of NZT. Substitution of the Ti 4+ by Zn 2+ in the BT system resulted in weakening of bondingforce between the B-site ion and oxygen ion of ABO 3 perovskite structure, leading to a reduced phase transition temperature (T C ), which is in consistence with earlier results that T C shifts to lower temperature with the substitution of the Ti-site by Zn 2+ in BT system 30. room temperature.…”

Pinning effects of dislocations on vortex domain structure in ferroelectric nanodots

“…Furthermore, domain pattern, ferroelectric transition temperature, polarization, and other static properties (e.g., electrical conductance) are strongly modified near the "defective" regions. [9][10][11][12][13][14] Although it is still a long way toward "defect engineering," the revealed effects of defects in ferroelectrics during the past decades have provided us an exciting picture.…”

“…The case of low-dimensional ferroelectric nanostructures has been rarely studied, although defects commonly exist in these systems. 1,10 It is natural to wonder how defects influence the VDS in these systems. As with thin films or bulk systems, we are interested in asking two questions.…”

Strain induced vortex-to-uniform polarization transitions in soft-ferroelectric nanoparticles

“…46 Remarkably, the planar ðp x ; p y Þ nature of the polarization density in the layered PSTO geometry, as well as it being unconstrained in magnitude (including an ability to vanish altogether at relatively low energy costs), allows this system to avoid the divergence of the free energy without forming a topological defect. That is, instead of dipole moments near the disk center being rotated to point in the out-of-plane direction, like in most other studied FE nanoparticles, [11][12][13][14][15][16][17][18][19][20][21][22] the polarization in that area gradually disappears, creating an unpolarized region at the vortex core. The described polarization patterns in unstrained disks are shown in Fig.…”

“…In contrast, the properties of ferroelectric (FE) nanostructures are less understood, and similar notions of topologically ordered states have emerged only recently sparked by a theoretical prediction of polarization vortex states in ferroelectric nanodisks and nanorods. 9 Since then, a substantial number of FE nanostructure transitions involving a variety of exotic states, including vortices and skyrmions, 10 and induced by elastic strains [11][12][13] or applied electric fields [14][15][16][17][18] has been proposed by simulation and modeling. [19][20][21][22] The purpose of this work is to demonstrate that vortex-like states can occur in a soft layered-FE material and that it is possible to control the transition between vortex-like and uniform-polarization orderings by applying stress.…”