Molecular dynamics studies of radiation induced phase transitions in La2Zr2O7 pyrochlore

We present a review of our past works and some new results on the molecular dynamics simulation of La2Zr2O7 pyrochlore phase transitions under irradiation. The transition sequence observed experimentally from ordered pyrochlore to disordered fluorite then to amorphous is reproduced. New results, including simulations of electron diffraction images, are given on the relationship between oxygen and cationic disorder. We find that there is no need to call upon preliminary oxygen disorder to reproduce the experimental diffraction patterns. Thermokinetics of the transitions are simulated by the continuous accumulation of cationic Frenkel pairs. The increase of the amorphization dose with temperature and the existence of a critical temperature are obtained. The leading role of Zr cation disorder is highlighted. (c) 2006 Elsevier B.V. All rights reserved.