Complex Structural Disorder in a Polar Orthorhombic Perovskite Observed through the Maximum Entropy Method/Rietveld Technique



Manjon-Sanz, Alicia Maria, Surta, T Wesley, Mandal, Pranab, Corkett, Alex J, Niu, Hongjun, Nishibori, Eiji, Takata, Masaki, Claridge, John Bleddyn and Rosseinsky, Matthew J
(2022) Complex Structural Disorder in a Polar Orthorhombic Perovskite Observed through the Maximum Entropy Method/Rietveld Technique. CHEMISTRY OF MATERIALS, 34 (1). pp. 29-42.

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Abstract

Ambient pressure stable perovskite oxides with all Bi3+ on the A-site are rare, with only four examples known. Due to the lone pair on Bi3+, these materials are seen as the best alternative to Pb-based piezoelectrics, which are used widely in society. The industry standard piezoelectric, Pb (Zr1 - xTix)O3, relies on the [001] polarization of PbTiO3, but there are currently no ambient pressure stable Bi-based perovskites with this polarization vector, preventing the creation of an analogous system. We present the full structural analysis of the orthorhombic phase of (1 - x)Bi (Ti3/8Fe2/8Mg3/8)O3 - xCaTiO3, which crystallizes in Pna21 symmetry with [001] polarization. This symmetry is rare and has only been reported twice for perovskites at ambient conditions. Analysis of maximum entropy method (MEM) models using synchrotron radiation powder X-ray diffraction reveals a disordered A-site configuration, and the MEM/Rietveld technique generates a structural model of this extreme disorder. Combined Rietveld analysis of X-ray and neutron diffraction data yields an accurate description of the local A-site configuration, which we use to understand our dielectric, ferroelectric, and piezoelectric measurements. These results give insight into how to stabilize this unique symmetry and inspire new design principles for Bi-based piezoelectrics.

Item Type: Article
Uncontrolled Keywords: 3402 Inorganic Chemistry, 34 Chemical Sciences, 3406 Physical Chemistry
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 17 Aug 2022 08:42
Last Modified: 20 Jun 2024 19:09
DOI: 10.1021/acs.chemmater.1c01979
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3161447