Senn, Mark S., Bird, T. A., Woodland-Scott, J., Lu, H., Wharmby, T. M., Chen, J. and Goodwin, A. L. (2020) Data for Anharmonicity and scissoring modes in negative thermal expansion materials scf3 and cazrf6. [Dataset]

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Abstract

We use a symmetry-motivated approach to analysing X-ray pair distribution functions to study the mechanism of negative thermal expansion in two ReO3-like compounds; ScF3 and CaZrF6. Both average and local structure suggest that it is the flexibility of M-F-M linkages (M = Ca, Zr, Sc) due to dynamic rigid and semi-rigid "scissoring" modes that facilitates the observed NTE behaviour. The amplitudes of these dynamic distortions are greater for CaZrF6 than for ScF3, which corresponds well with the larger magnitude of the thermal expansion reported in the literature for the former. We show that this flexbility is enhanced in CaZrF6 due to the rock-salt ordering mixing the characters of two of these scissoring modes. Additionally, we show that in ScF3 anharmonic coupling between the modes responsible for the structural flexibility and the rigid unit modes contributes to the unusually high NTE behaviour in this material.

Item Type:	Dataset
Subjects:	Q Science > QC Physics Q Science > QD Chemistry
Divisions:	Faculty of Science > Chemistry
Type of Data:	Experimental data
Publisher:	Figshare
Official Date:	19 February 2020
Dates:	Date Event 3 December 2019 Submitted 19 February 2020 Published
Collection date:	Date from Date to 26 November 2018 27 November 2019
Status:	Not Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Open Access
Copyright Holders:	University of Warwick
Description:	ScF3 Data for paper https://arxiv.org/abs/1911.12695 / Phys Rev B 101, 064306 with information required to perform refinements is hosted online at Figshare at the official URL.
RIOXX Funder/Project Grant:	Project/Grant ID RIOXX Funder Name Funder ID EP/L015307/1 [EPSRC] Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266 UNSPECIFIED Royal Society of Chemistry http://dx.doi.org/10.13039/501100000704 UNSPECIFIED Royal Commission for the Exhibition of 1851 http://dx.doi.org/10.13039/501100000700
Related URLs:	Other
Contributors:	Contribution Name Contributor ID Depositor Bird, T. A. UNSPECIFIED

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