Titre du document / Document title

On the mechanism of the zircon-reidite pressure induced transformation

Auteur(s) / Author(s)

MARQUES M. ⁽¹⁾ ; CONTRERAS-GARCIA J. ⁽¹⁾ ; FLOREZ M. ⁽¹⁾ ; RECIO J. M. ⁽¹⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Departamento de Química Física y Analítica, Universidad de Oviedo, 33006 Oviedo, ESPAGNE

Résumé / Abstract

We report first principles results of a detailed investigation directed to elucidate mechanistic aspects of the zircon-reidite phase transition in ZrSiO₄. The calculated thermodynamic boundary is located around 5 GPa, and the corresponding thermal barrier, estimated from temperatures at which the transition is observed at zero and high pressure, is 133 kJ/mol. Under a martensitic perspective, we examine two different transition pathways at the thermodynamic transition pressure. First, the direct, displacive-like, tetragonal I4₁/a energetic profile is computed using the c/a ratio as the transformation parameter, and yields a very high activation barrier (236kJ/mol). Second, a quasi-monoclinic unit cell allows us to characterize a transition path from zircon (β = 90°) to reidite (β = 114.51°) with an activation barrier of around 80kl/mol at β=104°. This energy is somewhat lower than our previous estimation and supports the reconstructive nature of the transformation at the thermodynamic transition pressure.

Revue / Journal Title

The Journal of physics and chemistry of solids   ISSN 0022-3697 

Source / Source

Congrès
International Conference on the Study of Matter at Extreme Conditions SMEC2007, Miami Beach, Florida , ETATS-UNIS (15/04/2007)
2008, vol. 69, n^o 9 (216 p.)  [Document : 4 p.] (19 ref.), pp. 2277-2280 [4 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Oxford, ROYAUME-UNI  (1963) (Revue)

Mots-clés anglais / English Keywords

Zirconium silicate ; Thermodynamic properties ; Ab initio calculations ; High pressure ; Thermal barriers ; Phase transformations ; Pressure effects ;

Mots-clés français / French Keywords

ZrSiO4 ; Silicate de zirconium ; Propriété thermodynamique ; Calcul ab initio ; Haute pression ; Barrière thermique ; Transformation phase ; Effet pression ;

Mots-clés espagnols / Spanish Keywords

Zirconio silicato ;

Mots-clés d'auteur / Author Keywords

A. Oxides ; C. Ab initio calculations ; D. Phase transitions ; D. Thermodynamic properties ;

Localisation / Location

INIST-CNRS, Cote INIST : 8204, 35400018533936.0340