The local-structure and radiation resistance of Ln3TaO7 (Ln = Y, Sm, Gd)

Domains of the weberite structure has been found in both intrinsic and extrinsic disordered-pyrochlore oxides. Here we report a study of the local structure of the weberite structure-type Ln₃TaO₇ (Ln = Y, Sm, Gd) and their response to ion beam irradiation. All pristine compositions exhibit C222₁ structures at both local and long-range scales. Upon irradiation up to 1×10¹⁵ ions/cm², Ln₃TaO₇ (Ln = Y, Sm, Gd) maintained an ordered weberite structure with a unit cell volume expansion of less than 2.5%. Nanoindentation measurements demonstrate that these oxides possess excellent mechanical stability under radiation exposure. The observed radiation resistance and mechanical robustness suggest that Ln₃TaO₇ oxides are promising candidate materials for applications in high-radiation fields.