Negatively Charged In-Plane and Out-Of-Plane Domain Walls with Oxygen-Vacancy Agglomerations in a Ca-Doped Bismuth-Ferrite Thin Film.
van Aken, Peter A
ACS applied electronic materials
MetadataShow full item record
Haselmann, U., Suyolcu, Y. E., Wu, P., Ivanov, Y. P., Knez, D., van Aken, P. A., Chu, Y., & et al. (2021). Negatively Charged In-Plane and Out-Of-Plane Domain Walls with Oxygen-Vacancy Agglomerations in a Ca-Doped Bismuth-Ferrite Thin Film.. ACS applied electronic materials, 3 (10), 4498-4508. https://doi.org/10.1021/acsaelm.1c00638
The interaction of oxygen vacancies and ferroelectric domain walls is of great scientific interest because it leads to different domain-structure behaviors. Here, we use high-resolution scanning transmission electron microscopy to study the ferroelectric domain structure and oxygen-vacancy ordering in a compressively strained Bi<sub>0.9</sub>Ca<sub>0.1</sub>FeO<sub>3-δ</sub> thin film. It was found that atomic plates, in which agglomerated oxygen vacancies are ordered, appear without any periodicity between the plates in out-of-plane and in-plane orientation. The oxygen non-stoichiometry with δ ≈ 1 in FeO<sub>2-δ</sub> planes is identical in both orientations and shows no preference. Within the plates, the oxygen vacancies form 1D channels in a pseudocubic  direction with a high number of vacancies that alternate with oxygen columns with few vacancies. These plates of oxygen vacancies always coincide with charged domain walls in a tail-to-tail configuration. Defects such as ordered oxygen vacancies are thereby known to lead to a pinning effect of the ferroelectric domain walls (causing application-critical aspects, such as fatigue mechanisms and countering of retention failure) and to have a critical influence on the domain-wall conductivity. Thus, intentional oxygen vacancy defect engineering could be useful for the design of multiferroic devices with advanced functionality.
External DOI: https://doi.org/10.1021/acsaelm.1c00638
This record's URL: https://www.repository.cam.ac.uk/handle/1810/332191
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/