The irradiation effects of Gd2Hf2O7 and Gd2Ti2O7

In this report, we present dramatically different behavior between isostructural Gd2Hf2O7 and Gd2Ti2O7 pyrochlore using 400 keV Ne2+ irradiation under cryogenic conditions (∼77 K), in which the lattice volume of the irradiated layer of Gd2Ti2O7 increased with ion fluence up to 1 × 1015 ions/cm2, whereas, the lattice volume of the irradiated layer of Gd2Hf2O7 decreased with increasing fluence from 1 × 1015 to 6 × 1016 ions/cm2. The cation radius ratio rA/rB, the bond-type of A–O and B–O bonds, the order-to-disorder transition energy of Gd2Hf2O7 and Gd2Ti2O7, temperature–composition (T–C) phase diagrams of HfO2–Gd2O3 and TiO2–Gd2O3 mixtures were used to explain the response of Gd2Hf2O7 and Gd2Ti2O7 to ion irradiation-induced structure transformation.

► We first study on the Ne ion irradiation effects on Gd2Hf2O7 and Gd2Ti2O7.
► Gd2Hf2O7 is more radiation tolerant than Gd2Ti2O7.
► The lattice volume of the irradiated Gd2Ti2O7 increased with increasing ion dose.
► The lattice volume of the irradiated Gd2Hf2O7 decreased with increasing ion dose.
► We explain the reversed behavior of Gd2Hf2O7 and Gd2Ti2O7.