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Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
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Topological phase transformations and intrinsic size effects in ferroelectric nanoparticles
John Mangeri1, Yomery Espinal2, Andrea Jokisaari3
1Department of Physics, University of Connecticut, Storrs, CT, USA. john.mangeri@uconn.edu.
Nanoscale
|January 12, 2017
Summary
Ferroelectric nanoparticle composites exhibit tunable dielectric properties. Particle size critically influences polarization patterns, with a vanishing ferroelectricity threshold observed for nanoparticles below a specific diameter.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Ferroelectric nanoparticle composites are explored for electronic and energy harvesting devices.
- Understanding particle size, shape, and arrangement effects on functionality is crucial.
- Current knowledge on ferroelectric behavior in composite materials is incomplete.
Purpose of the Study:
- To investigate polarization behavior in spherical ferroelectric nanoparticles (PbTiO3 or BaTiO3) within dielectric matrices.
- To elucidate the impact of particle size, material choice, and matrix permittivity on ferroelectric properties.
- To determine the critical particle size below which ferroelectricity disappears.
Main Methods:
- Utilized time-dependent Ginzburg-Landau theory.
- Employed coupled-physics finite-element-method simulations.
- Analyzed polarization topology and electric field responses.
Main Results:
- Equilibrium polarization topology depends strongly on particle diameter and material composition.
- Monodomain, vortex-like, and multidomain patterns were observed.
- Radically different polarization vs. electric field responses were found, leading to tunable dielectric properties.
- A critical particle size below which ferroelectricity vanishes was identified for both PbTiO3 and BaTiO3 nanoparticles.
Conclusions:
- Particle size is a key factor in determining ferroelectric behavior and dielectric properties of composite materials.
- The vanishing ferroelectricity threshold is dependent on nanoparticle material and surrounding matrix permittivity.
- Simulation results provide a basis for experimental observation and design of novel ferroelectric nanodevices.
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