Title :

Diffusion mechanism of bound Schottky defect in magnesium oxide

Author(s) :

Mahmoud, Sami [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Carrez, Philippe [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Landeiro Dos Reis, Marie [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Mousseau, Normand [Auteur]
Regroupement Québécois sur les Matériaux de Pointe [RQMP]
Département de Physique [Montréal]
Cordier, Patrick [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Institut universitaire de France [IUF]

Journal title :

Physical Review Materials

Abbreviated title :

Phys. Rev. Materials

Volume number :

5

Pages :

033609

Publisher :

American Physical Society (APS)

Publication date :

2021-03-25

ISSN :

2475-9953

English keyword(s) :

Point defects
Self-diffusion

HAL domain(s) :

Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Planète et Univers [physics]/Sciences de la Terre

English abstract : [en]

In simple ionic crystals, intrinsic point defects must satisfy electrical neutrality and exist as Schottky defects. In magnesium oxide (MgO), a Schottky defect is then a combination of anionic and cationic vacancies. Since ...
Show more >In simple ionic crystals, intrinsic point defects must satisfy electrical neutrality and exist as Schottky defects. In magnesium oxide (MgO), a Schottky defect is then a combination of anionic and cationic vacancies. Since vacancies are charged, the stable configuration of the Schottky defect corresponds to a bound pair of vacancies of opposite signs. In this study, we investigate the kinetics of formation and migration of such a bound pair on long timescales reaching in some cases thousands of seconds using the kinetic activation-relaxation technique, an off-lattice kinetic Monte Carlo method with an event catalog built on-the-fly during static molecular simulations. We show that the diffusion of this bound Schottky defect involves the migration of vacancies bounded to the first and third neighbor sites of the crystal structure with an apparent migration energy which cannot be inferred from the migration energies expected from isolated defects. Overall, this study gives insights and constraints on the oxygen diffusion mechanism reported experimentally in high-purity MgO samples.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

European Project :

Rheology of Earth materials: closing the gap between TIMEscales in the laboratory and in the MANtle

Administrative institution(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Plasticité

Submission date :

2021-03-26T10:09:12Z
2021-03-26T15:45:00Z