Oxygen defects stabilize the crystal structure of MgAl2O4 spinel under irradiation

The kinetics of phase transformation under irradiation of MgAl2O4 spinel has been explored using molecular dynamics simulations. The irradiation damage has been simulated by Frenkel pairs accumulation in the crystal at 300 K. The phase transformation from spinel to disordered spinel structure and then to rock-salt structure has been observed in the process of defect accumulation, which is consistent with experimental measurements. Oxygen Frenkel pairs enhance the critical dose for phase transformation and the ability to preserve spinel structure under irradiation. The radiation induced enhancement of O-O interaction might play a key role in stabilization. (C) 2019 Elsevier B.V. All rights reserved.