Dynamic Conductivity of Ferroelectric Domain Walls in BiFeO₃

Abstract

Topological walls separating domains of continuous polarization, magnetization, and strain in ferroic materials hold promise of novel electronic properties, that are intrinsically localized on the nanoscale and that can be patterned on demand without change of material volume or elemental composition. We have revealed that ferroelectric domain walls in multiferroic BiFeO(3) are inherently dynamic electronic conductors, closely mimicking memristive behavior and contrary to the usual assumption of rigid conductivity. Applied electric field can cause a localized transition between insulating and conducting domain walls, tune domain wall conductance by over an order of magnitude, and create a quasicontinuous spectrum of metastable conductance states. Our measurements identified that subtle and microscopically reversible distortion of the polarization structure at the domain wall is at the origin of the dynamic conductivity. The latter is therefore likely to be a universal property of topological defects in ferroelectric semiconductors.

Piezoelectric nonlinearity and frequency dispersion of the direct piezoelectric response of BiFeO3 ceramics

“…50 In addition, formation of head-to-head or tailto-tail domain-wall configurations, as discussed by Maksymovych et al, 64 could also lead to accumulation of compensating charges at the wall. The formation of charged domains walls (head-to-head or tail-to-tail) was recently demonstrated by piezoforce microscopy (PFM) during switching of a (111) pc oriented BiFeO 3 thin film.…”

Regular nanodomain vertex arrays in BiFeO3single crystals

“…The ferroelastic domains of BFO may have a certain polarization discontinuity perpendicular to the domain wall, which is supposed to be the main cause for the high conductivity of these domain walls and should also play a certain role in the abnormal photovoltaic effect in BFO. [10][11][12] The antiferromagnetic plane is coupled with the polarization direction in such a way that the magnetic easy plane in which the spins rotate is perpendicular to the polarization vector, i.e., the [111] crystallographic direction. Ferroelastic switching in BFO also implies switching of these magnetic planes, with a significant impact on the electrical control of magnetic properties in multiferroic devices.…”

Oxygen-vacancy effect on structural, magnetic, and ferroelectric properties in multiferroic YMnO3 single crystals

“…9,10 Multiferroic domain walls (DWs), where the ferroic order parameters couple, have been discovered and found to be critical for multiferroicity, which is controllable via material design and external fields. 11 The defects, including structural, nonstoichiometric, and topological defects, are expected to possess distinct electronic properties at multiferroic DWs, which, in turn, enhances magnetoelectric coupling in multiferroics.…”