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Atomistic simulations of surface segregation of defects in solid oxide electrolytes / Hark B. Lee in Acta materialia, Vol. 58 N° 6 (Avril 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2197–2206 Titre : Atomistic simulations of surface segregation of defects in solid oxide electrolytes Type de document : texte imprimé Auteurs : Hark B. Lee, Auteur ; Friedrich B. Prinz, Auteur ; Wei Cai, Auteur Année de publication : 2011 Article en page(s) : pp. 2197–2206 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Segregation  Monte  Carlo  Molecular  dynamics  Yttria-stabilized  zirconia  Gadolinia-doped  ceria Résumé : We performed atomistic simulations of yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC) to study the segregation of point defects near (1 0 0) surfaces. A hybrid Monte Carlo–molecular dynamics algorithm was developed to sample the equilibrium distributions of dopant cations and oxygen vacancies. The simulations predict an increase of dopant concentration near the surface, which is consistent with experimental observations. Oxygen vacancies are also found to segregate in the first anion layer beneath the surface and to be depleted in the subsequent anion layers. While the ionic size mismatch between dopant and host cations has been considered as a driving force for dopant segregation to the surface, our simulations show that the correlation between individual point defects plays a dominant role in determining their equilibrium distributions. This correlation effect leads to more pronounced dopant segregation in GDC than in YSZ, even though the size mismatch between dopant and host cations is much greater in YSZ than in GDC. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008398 [article] Atomistic simulations of surface segregation of defects in solid oxide electrolytes [texte imprimé] / Hark B. Lee, Auteur ; Friedrich B. Prinz, Auteur ; Wei Cai, Auteur . - 2011 . - pp. 2197–2206. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 6 (Avril 2010) . - pp. 2197–2206 Mots-clés : Segregation  Monte  Carlo  Molecular  dynamics  Yttria-stabilized  zirconia  Gadolinia-doped  ceria Résumé : We performed atomistic simulations of yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC) to study the segregation of point defects near (1 0 0) surfaces. A hybrid Monte Carlo–molecular dynamics algorithm was developed to sample the equilibrium distributions of dopant cations and oxygen vacancies. The simulations predict an increase of dopant concentration near the surface, which is consistent with experimental observations. Oxygen vacancies are also found to segregate in the first anion layer beneath the surface and to be depleted in the subsequent anion layers. While the ionic size mismatch between dopant and host cations has been considered as a driving force for dopant segregation to the surface, our simulations show that the correlation between individual point defects plays a dominant role in determining their equilibrium distributions. This correlation effect leads to more pronounced dopant segregation in GDC than in YSZ, even though the size mismatch between dopant and host cations is much greater in YSZ than in GDC. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645409008398