2.7 MeV Ar11+ ion irradiation induced structural evolution in Lu2(Ti2-Lu )O7-/2 pyrochlores

Abstract This paper aims to study the radiation effects of nonstoichiometric pyrochlore series Lu 2 (Ti 2- x Lu x )O 7- x /2 ( x = 0–0.667). Polycrystalline Lu 2 (Ti 2- x Lu x )O 7- x /2 samples were irradiated with 2.7 MeV Ar 11+ ions up to a fluence of 8 × 10 14 ions/cm 2 . The irradiated samples were characterized using grazing incidence X-ray diffraction technique. The results reveal that Lu 2 (Ti 2- x Lu x )O 7- x /2 samples undergo significant amorphization and lattice swelling upon irradiation. Specifically, the amorphization process is predominantly driven by ballistic nuclear energy deposition of Ar 11+ ions at this energy regime, which can be well described by a direct-impact/defect-stimulated model. Both the amorphization fraction and the relative variation of lattice parameter decrease with increasing x , showing a strong dependence on the chemical composition. The results are then discussed in the framework of the structural disorder and recovery ability from damage, applying an atomic layer model.