The Role of Antisite Disorder on Pre-Amorphization Swelling in Titanate Pyrochlores
Résumé
Ion irradiation experiments and atomistic computer simulations were used to demonstrate that irradiation-induced lattice swelling in a complex oxide, Lu2Ti2O7, is due initially to the formation of cation antisite defects. X-ray diffraction (XRD) revealed that cation antisite formation correlates directly with pre-amorphization lattice swelling. XRD indicates that the volume per cation antisite pair is approximately 12 cubic angstroms. First principles calculations revealed that lattice swelling is best explained by near-neighbor antisite defects. Temperature accelerated dynamics simulations indicate that cation Frenkel defects are metastable and decay to form neighboring antisite defects.