Pressure and temperature phase diagram of Gd$_2$Ti$_2$O$_7$ under irradiation

G. Catillon (1) , A. Chartier (2)

1 UPEC UP12 - Université Paris-Est Créteil Val-de-Marne - Paris 12
2 SCCME - Service de la Corrosion et du Comportement des Matériaux dans leur Environnement

The pressure and temperature phase diagram of Gd$_2$Ti$_2$O$_7$ under irradiation are calculated by means of molecular dynamics calculations. The critical temperature for amorphization obeys a linear law with pressure. Gd$_2$Ti$_2$O$_7$ under irradiation transits towards the fluorite above this temperature and amorphizes below. The configuration of the Ti interstitial reveals to be the key of the amorphizability of Gd$_2$Ti$_2$O$_7$. Its stability depends upon disorder and pressure. Low pressure promotes the stabilization of Ti linked-polyhedra that drive the system to the amorphous state under irradiation. Conversely, high pressure activates its destabilization to interstitials that recombine with vacancies, driving the system to the fluorite structure under irradiation

Domaines: Acoustique [physics.class-ph]; Gestion et management; Physique Nucléaire Expérimentale [nucl-ex]; Matériaux; Chimie analytique

G. Catillon, A. Chartier. Pressure and temperature phase diagram of Gd$_2$Ti$_2$O$_7$ under irradiation. Journal of Applied Physics, 2014, 116 (19), pp.193502. ⟨10.1063/1.4901577⟩. ⟨cea-03189947⟩