Defect structures and migration mechanisms in oxide pyrochlores

M.P. van Dijk; A.J. Burggraaf; A.N. Cormack; C.R.A. Catlow

doi:10.1016/0167-2738(85)90067-0

Defect structures and migration mechanisms in oxide pyrochlores

M.P. van Dijk, A.J. Burggraaf, A.N. Cormack, C.R.A. Catlow

Inorganic Materials Science

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Abstract

Using computer simulation techniques the defect structure and oxygen ion migration mechanism of oxide pyrochlores (eg. Gd₂Zr₂O₇) was investigated in order to explain the decreased activation enthalpy for oxygen ion conductivity as a function of order. Shell model potentials were found to be necessary in order to obtain sufficiently accurate physical properties for the pyrochlore compound. The oxygen Frenkel defect consisting of ‘a split 48f vacancy’ and 8b interstitial appeared to be the most stable instrinsic defect, but vacancies related to extended defect structures may play an important role in the diffusion mechanism too. The migration mechanism of oxygen ions is mainly based on 48f-48f jumps and involve 0.9 eV barrier energy, comparable with the experimental activation enthalpies of 70–85 kJ/mol.

Original language	English
Pages (from-to)	159-167
Journal	Solid state ionics
Volume	17
Issue number	25
DOIs	https://doi.org/10.1016/0167-2738(85)90067-0
Publication status	Published - 1985

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title = "Defect structures and migration mechanisms in oxide pyrochlores",

abstract = "Using computer simulation techniques the defect structure and oxygen ion migration mechanism of oxide pyrochlores (eg. Gd2Zr2O7) was investigated in order to explain the decreased activation enthalpy for oxygen ion conductivity as a function of order. Shell model potentials were found to be necessary in order to obtain sufficiently accurate physical properties for the pyrochlore compound. The oxygen Frenkel defect consisting of {\textquoteleft}a split 48f vacancy{\textquoteright} and 8b interstitial appeared to be the most stable instrinsic defect, but vacancies related to extended defect structures may play an important role in the diffusion mechanism too. The migration mechanism of oxygen ions is mainly based on 48f-48f jumps and involve 0.9 eV barrier energy, comparable with the experimental activation enthalpies of 70–85 kJ/mol.",

author = "{van Dijk}, M.P. and A.J. Burggraaf and A.N. Cormack and C.R.A. Catlow",

year = "1985",

doi = "10.1016/0167-2738(85)90067-0",

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pages = "159--167",

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T1 - Defect structures and migration mechanisms in oxide pyrochlores

AU - van Dijk, M.P.

AU - Burggraaf, A.J.

AU - Cormack, A.N.

AU - Catlow, C.R.A.

PY - 1985

Y1 - 1985

N2 - Using computer simulation techniques the defect structure and oxygen ion migration mechanism of oxide pyrochlores (eg. Gd2Zr2O7) was investigated in order to explain the decreased activation enthalpy for oxygen ion conductivity as a function of order. Shell model potentials were found to be necessary in order to obtain sufficiently accurate physical properties for the pyrochlore compound. The oxygen Frenkel defect consisting of ‘a split 48f vacancy’ and 8b interstitial appeared to be the most stable instrinsic defect, but vacancies related to extended defect structures may play an important role in the diffusion mechanism too. The migration mechanism of oxygen ions is mainly based on 48f-48f jumps and involve 0.9 eV barrier energy, comparable with the experimental activation enthalpies of 70–85 kJ/mol.

AB - Using computer simulation techniques the defect structure and oxygen ion migration mechanism of oxide pyrochlores (eg. Gd2Zr2O7) was investigated in order to explain the decreased activation enthalpy for oxygen ion conductivity as a function of order. Shell model potentials were found to be necessary in order to obtain sufficiently accurate physical properties for the pyrochlore compound. The oxygen Frenkel defect consisting of ‘a split 48f vacancy’ and 8b interstitial appeared to be the most stable instrinsic defect, but vacancies related to extended defect structures may play an important role in the diffusion mechanism too. The migration mechanism of oxygen ions is mainly based on 48f-48f jumps and involve 0.9 eV barrier energy, comparable with the experimental activation enthalpies of 70–85 kJ/mol.

U2 - 10.1016/0167-2738(85)90067-0

DO - 10.1016/0167-2738(85)90067-0

M3 - Article

VL - 17

SP - 159

EP - 167

JO - Solid state ionics

JF - Solid state ionics

SN - 0167-2738

IS - 25

ER -

Defect structures and migration mechanisms in oxide pyrochlores

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