Domain wall conductivity as the origin of enhanced domain wall dynamics in polycrystalline BiFeO3

Despite their primary importance in modern nanoelectronics, conductive domain walls (DWs) can also have a marking effect on the macroscopic response of polycrystalline ferroelectrics. In particular, a large nonlinear piezoelectric response at sub-Hz driving-field frequencies has been previously obse...

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Bibliographic Details
Published in:Journal of applied physics 2020-08, Vol.128 (6)
Main Authors: Makarovic, Maja, Bayir, Mustafa Çağri, Ursic, Hana, Bradesko, Andraz, Rojac, Tadej
Format: Article
Language:English
Subjects:
Anisotropy
Applied physics
Bismuth compounds
Domain walls
Electric fields
Electrical resistivity
Ferroelectric materials
Ferroelectricity
Ferroelectrics
Nanoelectronics
Nonlinear control
Nonlinear response
Nonlinearity
Piezoelectricity
Polycrystals
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Summary:Despite their primary importance in modern nanoelectronics, conductive domain walls (DWs) can also have a marking effect on the macroscopic response of polycrystalline ferroelectrics. In particular, a large nonlinear piezoelectric response at sub-Hz driving-field frequencies has been previously observed in BiFeO3, which was linked to the conductive nature of the DWs but whose exact origin has never been explained. In this study, by carefully designing the local conductivity in BiFeO3 using chemical doping, we found that the low-frequency piezoelectric nonlinearity is only observed in the sample with a large fraction of conductive DWs. Supported by nonlinear Maxwell–Wagner modeling, we propose that this large response originates from DW displacements inside a specific set of grains or grain clusters in which the internal electric fields are enhanced due to M-W effects. We thus show that these effects likely arise due to the pronounced local anisotropy in the electrical conductivity, varying from grain to grain, whose origin lies in the conductive DWs themselves. The results demonstrate the possibility of controlling the global nonlinear properties of polycrystalline ferroelectrics by engineering local properties.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0017374