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A theoretical study of intrinsic point defects and defect clusters in magnesium aluminate spinel

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posted on 2015-11-06, 15:14 authored by Christopher A. Gilbert, Roger Smith, Steven KennySteven Kenny, S.T. Murphy, R.W. Grimes, J.A. Ball
Point and small cluster defects in magnesium aluminate spinel have been studied from a first principles viewpoint. Typical point defects that occur during collision cascade simulations are cation anti-site defects, which have a small formation energy and are very stable, O and Mg split interstitials and vacancies. Isolated Al interstitials were found to be energetically unfavourable but could occur as part of a split Mg-Al pair or as a three atom-three vacancy Al ‘ring’ defect, previously observed in collision cascades using empirical potentials. The structure and energetics of the defects were investigated using density functional theory (DFT) and the results compared to simulations using empirical fixed-charge potentials. Each point defect was studied in a variety of supercell sizes in order to ensure convergence. It was found that empirical potential simulations significantly overestimate formation energies, but that the type and relative stability of the defects are well-predicted by the empirical potentials both for point defects and small defect clusters.

History

School

  • Science

Department

  • Mathematical Sciences

Published in

JOURNAL OF PHYSICS-CONDENSED MATTER

Volume

21

Issue

27

Pages

? - ? (7)

Citation

GILBERT, C.A. ...et al., 2009. A theoretical study of intrinsic point defects and defect clusters in magnesium aluminate spinel. Journal of Physics-Condensed Matter, 21:275406.

Publisher

© IOP PUBLISHING LTD

Version

  • AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2009

Notes

This article was published in the Journal of Physics: Condensed Matter [© IOP Publishing Ltd.] and the definitive version is available at: http://dx.doi.org/10.1088/0953-8984/21/27/275406

ISSN

0953-8984

Language

  • en