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Ge et al. Microstructures 2023;3:2023026 Microstructures
DOI: 10.20517/microstructures.2023.13

Research Article Open Access

180° head-to-head flat domain walls in single crystal
BiFeO 3

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Wanbing Ge , Richard Beanland 1 , Marin Alexe , Quentin Ramasse , Ana M. Sanchez 1
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Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
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SuperSTEM Laboratory, SciTech Daresbury, Keckwick Lane, Warrington WA4 4AD, UK.
Correspondence to: Prof. Richard Beanland, Department of Physics, University of Warwick, Coventry CV4 7AL, UK. E-mail:
R.Beanland@warwick.ac.uk
How to cite this article: Ge W, Beanland R, Alexe M, Ramasse Q, Sanchez AM. 180° head-to-head flat domain walls in single
crystal BiFeO . Microstructures 2023;3:2023026. https://dx.doi.org/10.20517/microstructures.2023.13
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Received: 20 Mar 2023 First Decision: 12 Apr 2023 Revised: 28 Apr 2023 Accepted: 12 May 2023 Published: 12 Jun 2023

Academic Editor: Shujun Zhang Copy Editor: Fangling Lan Production Editor: Fangling Lan

Abstract
We investigate flux-grown BiFeO crystals using transmission electron microscopy (TEM). This material has an
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intriguing ferroelectric structure of domain walls with a period of approximately 100 nm, alternating between flat
and sawtooth morphologies. We show that all domain walls are of 180° type and that the flat walls, lying on (112)
planes, are reconstructed with an excess of Fe and a deficiency of Bi. This reconstruction is similar to that observed
in several previous studies of deposited layers of BiFeO . The negative charge of the reconstructed layer induces
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head-to-head polarisation in the surrounding material and a rigid-body shift of one domain relative to the other.
These characteristics pin the flat 180° domain walls and determine the domain structure of the material. Sawtooth
180° domain walls provide the necessary reversal of polarisation between flat walls. The high density of immobile
domain walls suppresses the ferroelectric properties of the material, highlighting the need for careful control of
growth conditions.
Keywords: Bismuth ferrite, ferroelectric domains, 180° domain walls, reconstructed domain walls

INTRODUCTION
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BiFeO is arguably the most investigated multiferroic material , simultaneously showing ferroelectric,
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antiferromagnetic, and ferroelastic order at room temperature . The coupling of ferroelectric and
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ferromagnetic properties makes it ideal for the promising application of mutual control of electrical and

© The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0
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