Accumulation and recovery of disorder in Au2+-irradiated Cd2Nb2O7

Cadmium niobate pyrochlore (Cd2Nb2O7) single crystals have been irradiated at 150, 300, 450 and 600 K using 1.0 MeV Au2+ ions over fluences ranging from 0.01 to 3.5 ions/nm2. The relative disorder on the Cd sublattice in the as-irradiated Cd2Nb2O7 has been analyzed based on in situ 3.0 MeV He+ Rutherford backscattering spectrometry along the 〈1 0 0〉-axial channeling direction. The results show that the crystal can be readily amorphized under the Au2+ irradiation at or below 450 K; however, the relative Cd disorder tends to saturate at 600 K, and full amorphization does not occur at doses up to 5 dpa. Isochronal annealing (20 min) also has been performed at temperatures from 180 to 295 K for samples irradiated at 150 K. Thermal recovery of the disorder has been observed below room temperature.