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Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics

Diffusion in complex oxides is critical to ionic transport, radiation damage evolution, sintering, and aging. In complex oxides such as pyrochlores, anionic diffusion is dramatically affected by cation disorder. However, little is known about how disorder influences cation transport. Here, we report...

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Autores principales: Perriot, Romain, Uberuaga, Blas P., Zamora, Richard J., Perez, Danny, Voter, Arthur F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5606988/
https://www.ncbi.nlm.nih.gov/pubmed/28931812
http://dx.doi.org/10.1038/s41467-017-00708-z
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author Perriot, Romain
Uberuaga, Blas P.
Zamora, Richard J.
Perez, Danny
Voter, Arthur F.
author_facet Perriot, Romain
Uberuaga, Blas P.
Zamora, Richard J.
Perez, Danny
Voter, Arthur F.
author_sort Perriot, Romain
collection PubMed
description Diffusion in complex oxides is critical to ionic transport, radiation damage evolution, sintering, and aging. In complex oxides such as pyrochlores, anionic diffusion is dramatically affected by cation disorder. However, little is known about how disorder influences cation transport. Here, we report results from classical and accelerated molecular dynamics simulations of vacancy-mediated cation diffusion in Gd(2)Ti(2)O(7) pyrochlore, on the microsecond timescale. We find that diffusion is slow at low levels of disorder, while higher disorder allows for fast diffusion, which is then accompanied by antisite annihilation and reordering, and thus a slowing of cation transport. Cation diffusivity is therefore not constant, but decreases as the material reorders. We also show that fast cation diffusion is triggered by the formation of a percolation network of antisites. This is in contrast with observations from other complex oxides and disordered media models, suggesting a fundamentally different relation between disorder and mass transport.
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spelling pubmed-56069882017-09-22 Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics Perriot, Romain Uberuaga, Blas P. Zamora, Richard J. Perez, Danny Voter, Arthur F. Nat Commun Article Diffusion in complex oxides is critical to ionic transport, radiation damage evolution, sintering, and aging. In complex oxides such as pyrochlores, anionic diffusion is dramatically affected by cation disorder. However, little is known about how disorder influences cation transport. Here, we report results from classical and accelerated molecular dynamics simulations of vacancy-mediated cation diffusion in Gd(2)Ti(2)O(7) pyrochlore, on the microsecond timescale. We find that diffusion is slow at low levels of disorder, while higher disorder allows for fast diffusion, which is then accompanied by antisite annihilation and reordering, and thus a slowing of cation transport. Cation diffusivity is therefore not constant, but decreases as the material reorders. We also show that fast cation diffusion is triggered by the formation of a percolation network of antisites. This is in contrast with observations from other complex oxides and disordered media models, suggesting a fundamentally different relation between disorder and mass transport. Nature Publishing Group UK 2017-09-20 /pmc/articles/PMC5606988/ /pubmed/28931812 http://dx.doi.org/10.1038/s41467-017-00708-z Text en © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Perriot, Romain
Uberuaga, Blas P.
Zamora, Richard J.
Perez, Danny
Voter, Arthur F.
Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
title Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
title_full Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
title_fullStr Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
title_full_unstemmed Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
title_short Evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
title_sort evidence for percolation diffusion of cations and reordering in disordered pyrochlore from accelerated molecular dynamics
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5606988/
https://www.ncbi.nlm.nih.gov/pubmed/28931812
http://dx.doi.org/10.1038/s41467-017-00708-z
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