A model for out-of-phase boundary induced X-ray diffraction peak profile changes in Aurivillius oxide thin films
File(s)
Published version
Author(s)
Whatmore, Roger W
Dutta, Debismita
Keeney, Lynette
Type
Journal Article
Abstract
Layered crystal structures, such as the Ruddlesden–Popper and Aurivillius families of layered perovskites, have long been studied for their diverse range of functionalities. The Aurivillius family has been extensively studied for its ferroelectric properties and potential applications in various fields, including multiferroic memories. A new analytical model is presented here that explains how out-of-phase boundaries (OPBs) in epitaxial thin films of layered materials affect X-ray diffraction (XRD) peak profiles. This model predicts which diffraction peaks will split and the degree of splitting in terms of simple physical parameters that describe the nanostructure of the OPBs, specifically the structural displacement perpendicular to the layers when moving across the OPB, the angle made by the OPB at the thin-film–substrate interface, and the OPB periodicity and its statistical distribution. The model was applied to epitaxial thin films of two Aurivillius oxides, SrBi2(Ta,Nb)O9 (SBTN) and Bi4Ti3O12 (BiT), and its predictions were compared with experimental XRD data for these materials. The results showed good agreement between the predicted and observed peak splitting as a function of OPB periodicity for SBTN and for an XRD profile taken from a BiT thin film containing a well characterized distribution of OPBs. These results have proven the model's validity and accuracy. The model provides a new framework for analysing and characterizing this class of defect structures in layered systems containing OPBs.
Date Issued
2025-08-01
Date Acceptance
2025-05-06
Citation
Journal of Applied Crystallography, 2025, 58 (4), pp.1191-1204
ISSN
0021-8898
Publisher
International Union of Crystallography
Start Page
1191
End Page
1204
Journal / Book Title
Journal of Applied Crystallography
Volume
58
Issue
4
Copyright Statement
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
License URL
Identifier
10.1107/S1600576725004091
Subjects
Aurivillius phases
perovskites
layered structures
thin films
defects
modelling
out-of-phase boundaries
X-ray diffraction
peak splitting. Supporting information: this article has supporting information at journals.iucr.org/j
Publication Status
Published
Date Publish Online
2025-07-02