13 research outputs found
Fixed Volume Effect on Polar Properties and Phase Diagrams of Ferroelectric Semi-ellipsoidal Nanoparticles
For advanced applications in modern industry it is very important to reduce
the volume of ferroelectric nanoparticles without serious deterioration of
their polar properties. In many practically important cases fixed volume
(rather than fixed size) corresponds to realistic technological conditions of
nanoparticles fabrication. The letter is focused on the theoretical study of
the behavior of ferroelectric polarization, paramagnetoelectric coefficient and
phase diagrams of semi-ellipsoidal nanoparticles with fixed volume V. Our
approach combines the Landau-Ginzburg-Devonshire phenomenology, classical
electrostatics and elasticity theory. Our results show that the size effects of
the phase diagrams and polarization of semi-ellipsoidal BiFeO3 nanoparticles
nontrivially depends on V. These findings provide a path to optimize the polar
properties of nanoparticles by controlling their phase diagrams at a fixed
volume.Comment: 15 pages, 5 figures, we added the section IV. Paramagnetoelectric
(PME) coefficient at fixed volume in this version and changed title and
abstract accordingl
Low-Symmetry Monoclinic Ferroelectric Phase Stabilized by Oxygen Octahedra Rotations in Strained EuâSrâââTiOâ Thin Films
Using Landau-Ginzburg-Devonshire theory and phase-field modeling, we explore the complex interplay between a structural order parameter (oxygen octahedron rotation) and polarization in EuxSr1-xTiO3 thin films. Under a biaxially tensile strain, a low-symmetry monoclinic phase with in-plane ferroelectric polarization is found to be stabilized by antiferrodistortive oxygen octahedra tilts. The monoclinic phase is stable over a wide temperature range. It is characterized by a large number of energetically equivalent polar and structural twin domains. This work demonstrates the development of a spontaneous polarization and piezo- and pyroelectricity in a ferroelastic twin boundary arising from flexoelectric coupling and rotostriction
Universal Emergence of Spatially Modulated Structures Induced by Flexoantiferrodistortive Coupling in Multiferroics
We proved the existence of a universal flexoantiferrodistortive coupling as a necessary complement to the well-known flexoelectric coupling. The coupling is universal for all antiferrodistortive systems and can lead to the formation of incommensurate, spatially modulated phases in multiferroics. Our analysis can provide a self-consistent mesoscopic explanation for a broad range of modulated domain structures observed experimentally in multiferroics