Three-dimensional imaging of vortex structure in a ferroelectric nanoparticle driven by an electric field

Abstract

Topological defects of spontaneous polarization are extensively studied as templates for unique physical phenomena and in the design of reconfigurable electronic devices. Experimental investigations of the complex topologies of polarization have been limited to surface phenomena, which has restricted the probing of the dynamic volumetric domain morphology in operando. Here, we utilize Bragg coherent diffractive imaging of a single BaTiO3 nanoparticle in a composite polymer/ferroelectric capacitor to study the behavior of a three-dimensional vortex formed due to competing interactions involving ferroelectric domains. Our investigation of the structural phase transitions under the influence of an external electric field shows a mobile vortex core exhibiting a reversible hysteretic transformation path. We also study the toroidal moment of the vortex under the action of the field. Our results open avenues for the study of the structure and evolution of polar vortices and other topological structures in operando in functional materials under cross field configurations.

Spatially resolved steady-state negative capacitance

“…Here, we use STO/PTO superlattices as a model system that breaks into vortex like domains [16][17][18] .…”

“…We use the superlattices of SrTiO 3 /PbTiO 3 as our model Ferroelectric-Dielectric heterostructure system where a state of negative capacitance is expected to be stabilized in the equilibrium. In such superlattices vortex-like topologies [16][17][18] are observed as the dominant polarization pattern when the periodicity is optimal [19][20][21] . The defining characteristic of these topologies is the gradual suppression of polarization near the center of the vortex.…”

Boosting Photovoltaic Output of Ferroelectric Ceramics by Optoelectric Control of Domains

“…Also, when the material dimension and domain size were scaled down to nanolevel, surface sensitivity may become the major issue. Therefore, although it is not the focus of this study, a Bragg coherent diffractive imaging technique can be utilized in further studies concerning 3D vortex formed from competing interactions involving ferroelectric domains, especially for nanoparticles . This is an advanced method enabling in operando studies at synchrotrons.…”

Influence of Finite Size on the Electrocaloric Response in PbTiO3 Ceramics Near Room Temperature Using Landau Theory

“…With decreasing grain size, d , we see from Figure (a) to (c) that the spontaneous polarization is suppressed at a critical size. In nano ferroelectric particles, topological vortices in nanoparticles have been observed in experiments. In our simulations, for d = 150 nm, two polarization vortices are seen to exist in one plane as shown in Figure (a), with a maximum polarization of 0.5 C m −2 .…”