Studying the Polarization Switching in Polycrystalline BiFeO3 Films by 2D Piezoresponse Force Microscopy

Abstract

For rhombohedral multiferroelectrics, non-180° ferroelectric domain switching may induce ferroelastic and/or (anti-)ferromagnetic effect. So the determination and control of ferroelectric domain switching angles is crucial for nonvolatile information storage and exchange-coupled magnetoelectric devices. We try to study the intrinsic characters of polarization switching in BiFeO3 by introducing a special data processing method to determine the switching angle from 2D PFM (Piezoresponse Force Microscopy) images of randomly oriented samples. The response surface of BiFeO3 is first plotted using the piezoelectric tensor got from first principles calculations. Then from the normalized 2D PFM signals before and after switching, the switching angles of randomly oriented BiFeO3 grains can be determined through numerical calculations. In the polycrystalline BiFeO3 films, up to 34% of all switched area is that with original out-of-plane (OP) polarization parallel to the poling field. 71° polarization switching is more favorable, with the area percentages of 71°, 109° and 180° domain switching being about 42%, 29% and 29%, respectively. Our analysis further reveals that IP stress and charge migration have comparable effect on switching, and they are sensitive to the geometric arrangements. This work helps exploring a route to control polarization switching in BiFeO3, so as to realize desirable magnetoelectric coupling.

Magnetoelectric coupling and spin reorientation in BiFeO3

“…It was reported, that under electrical poling, polarization reorientation induces a spin flop in BFO . Direct changes in the nature of the antiferromagnetic domain structure in BFO thin films was observed by application of an external electric field by combining piezoresponse force microscopy imaging of ferroelectric domains and x‐ray photoemission electron microscopy imaging of antiferromagnetic domains . This research showed that the ferroelastic switching events (i.e., 71° and 109°) leads to a corresponding rotation of the magnetization plane in BFO thin films and has paved the way for further study of this material with intent of a control of ferromagnetism at room temperatures.…”

“…In several experimental studies it is shown that the magnetic sublattice rotates when an external electric field is applied in such a way that the magnetic planes and the vector of the electric polarization remain always orthogonal.…”

“…It was reported, that under electrical poling, polarization reorientation induces a spin flop in BFO . Direct changes in the nature of the antiferromagnetic domain structure in BFO thin films was observed by application of an external electric field by combining piezoresponse force microscopy imaging of ferroelectric domains and x‐ray photoemission electron microscopy imaging of antiferromagnetic domains .…”

Effects of the Hubbard U on density functional-based predictions of BiFeO3properties

“…Since the typical values of U eff chosen for Fe d orbitals in BFO lie between 3 and 5 eV [25,27,53,54,28,55,15,56,16], the accuracy of calculated unit cell parameters and P s depends more on the choice to use the PBE+U method at all, rather than on the particular value of U eff one chooses. Thus, within the range of U eff usually considered in the context of BFO, we conclude that the crystal structure varies negligibly with U eff .…”

Computer Aided Molecular Modeling of the Piezoelectric Properties of Ferroelectric Composites on the Base of Polyvinylidene Fluoride with Graphene and Graphene Oxide

“…Эти модели были основаны на аналогичных моделях и подходах, которые были разработаны и использовались в предыдущих работах [43][44][45]. Модели были симметризированы для получения более точных систем в процессе оптимизации.…”