St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  •   St Andrews Research Repository
  • University of St Andrews Research
  • University of St Andrews Research
  • University of St Andrews Research
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Exploring cation disorder in mixed-metal pyrochlore ceramics using 17O NMR spectroscopy and first-principles calculations

Thumbnail
View/Open
Fernandes_2021_Exploring_cation_disorder_in_mixed_MRC_CCBY.pdf (3.297Mb)
Date
08/2021
Author
Fernandes, Arantxa
Moran, Robert F
McKay, David
Griffiths, Ben
Herlihy, Anna
Whittle, Karl R
Dawson, Daniel McLean
Ashbrook, Sharon E.
Funder
European Research Council
EPSRC
The Royal Society
Grant ID
614290 - EXONMR
EP/M022501/1
WM150021
Keywords
QD Chemistry
TK Electrical engineering. Electronics Nuclear engineering
DAS
Metadata
Show full item record
Altmetrics Handle Statistics
Altmetrics DOI Statistics
Abstract
Characterising the local structures (e.g., the cation distribution) of mixed-metal ceramics by NMR spectroscopy is often challenging owing to the unfavourable properties (low γ, large quadrupole moment and/or low abundance) of many metal nuclei. 17O is an attractive option owing to the prevalence of oxygen within ceramics. The moderate γ and small quadrupole moment of 17O mean that the greatest barrier to accessing the information available from this nucleus is isotopic enrichment. We explore the challenges of ensuring uniform isotopic enrichment with 17O2(g) for the pyrochlore solid solutions, Y2SnxTi2–xO7, La2SnxZr2–xO7 and La2SnxHf2–xO7, demonstrating that high enrichment temperatures (900 °C for 12 h) are required. In addition, for sites with very high symmetry (such as the tetrahedral OY4 and OLa4 sites with CQ ≈ 0 present here), we demonstrate that quantitative 17O NMR spectra require correction for the differing contributions from the centreband of the satellite transitions, which can be as high as a factor of ~3.89. It is common to use first-principles calculations to aid in interpreting NMR spectra of disordered solids. Here, we use an ensemble modelling approach to ensure that all possible cation arrangements are modelled in the minimum possible number of calculations. By combining uniform isotopic enrichment, quantitative NMR spectroscopy and a comprehensive computational approach, we are able to show that the cation distribution in Y2SnxTi2–xO7 is essentially random, whereas in La2SnxZr2–xO7 and La2SnxHf2–xO7, OLa2SnZr and OLa2SnHf sites are slightly energetically disfavoured, leading to a weak preference for clustering of like cations.
Citation
Fernandes , A , Moran , R F , McKay , D , Griffiths , B , Herlihy , A , Whittle , K R , Dawson , D M & Ashbrook , S E 2021 , ' Exploring cation disorder in mixed-metal pyrochlore ceramics using 17 O NMR spectroscopy and first-principles calculations ' , Magnetic Resonance in Chemistry , vol. 59 , no. 9-10 . https://doi.org/10.1002/mrc.5140
Publication
Magnetic Resonance in Chemistry
Status
Peer reviewed
DOI
https://doi.org/10.1002/mrc.5140
ISSN
0749-1581
Type
Journal article
Rights
Copyright © 2021 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Description
Funding: Royal Society (Grant Number(s): Wolfson Merit Award); FP7 Ideas: European Research Council (Grant Number(s): 614290); Engineering and Physical Sciences Research Council (Grant Number(s): EP/M022501/1).
Collections
  • University of St Andrews Research
URI
http://hdl.handle.net/10023/21436

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter