Accumulation and thermal recovery of disorder in Au 2+-irradiated SrTiO 3

Abstract

Damage accumulation and thermal recovery processes have been investigated in single crystal SrTiO 3(1 0 0) irradiated with 1.0 MeV Au 2+ using in situ Rutherford backscattering spectrometry in channeling geometry (RBS/C). Samples were irradiated at temperatures of 170 and 300 K with ion fluences ranging from 0.10 to 0.40 Au 2+/nm 2. The in situ RBS/C analysis indicates that the relative disorder shows a strong sigmoidal dependence on ion dose. After an ion fluence of 0.30 Au 2+/nm 2 at 170 K, the buried region at the damage peak (∼60 nm) becomes fully amorphous, which corresponds to a dose of ∼0.8 displacement per atom (dpa). For irradiation at 300 K, an ion fluence of 0.40 Au 2+/nm 2 (∼1.1 dpa) is necessary to achieve an amorphous state at the damage peak. An analysis of the defects dechanneling factor suggests that the irradiated regions consist mostly of interstitial atoms or amorphous clusters. In situ thermal annealing experiments were performed to study damage recovery processes up to a maximum temperature of 870 K. The thermal recovery processes occur over a broad temperature range, and the disorder created by low ion fluences, 0.10–0.27 Au 2+/nm 2, is almost completely recovered after annealing at 870 K.