Domain-wall conduction in ferroelectric BiFeO3 controlled by accumulation of charged defects

Mobile charged defects, accumulated in the domain-wall region to screen polarization charges, have been proposed as the origin of the electrical conductivity at domain walls in ferroelectric materials. Despite theoretical and experimental efforts, this scenario has not been directly confirmed, leavi...

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Bibliographic Details
Published in:Nature materials 2017-03, Vol.16 (3), p.322-327
Main Authors: Rojac, Tadej, Bencan, Andreja, Drazic, Goran, Sakamoto, Naonori, Ursic, Hana, Jancar, Bostjan, Tavcar, Gasper, Makarovic, Maja, Walker, Julian, Malic, Barbara, Damjanovic, Dragan
Format: Article
Language:English
Subjects:
639/301/119/995
639/301/119/996
Accumulation
Annealing
Atmosphere
Biomaterials
Bismuth
Cations
Condensed Matter Physics
Conductivity
Electric properties
Electrical properties
Ferroelectrics
High temperature
Materials Science
Nanotechnology
Optical and Electronic Materials
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Summary:Mobile charged defects, accumulated in the domain-wall region to screen polarization charges, have been proposed as the origin of the electrical conductivity at domain walls in ferroelectric materials. Despite theoretical and experimental efforts, this scenario has not been directly confirmed, leaving a gap in the understanding of the intriguing electrical properties of domain walls. Here, we provide atomic-scale chemical and structural analyses showing the accumulation of charged defects at domain walls in BiFeO 3 . The defects were identified as Fe 4+ cations and bismuth vacancies, revealing p-type hopping conduction at domain walls caused by the presence of electron holes associated with Fe 4+ . In agreement with the p-type behaviour, we further show that the local domain-wall conductivity can be tailored by controlling the atmosphere during high-temperature annealing. This work has possible implications for engineering local conductivity in ferroelectrics and for devices based on domain walls. Domain walls in ferroelectrics are known to be conductive, but details of the precise mechanism are elusive. Atomic-scale structural and chemical characterization of domain walls in BiFeO 3 now reveals a build-up of charged defects.
ISSN:1476-1122
1476-4660
DOI:10.1038/nmat4799