Transmission Electron Microscopy and Molecular Dynamic Study of Ion Tracks in Nanocrystalline Y2Ti2O7: Particle Size Effect on Track Formation Threshold

Abstract

Structural effects in nanocrystalline pyrochlore Y2Ti2O7 induced by high energy heavy ions in a wide range of electronic stopping powers were studied by means of high-resolution transmission electron microscopy and molecular dynamics simulation considering the grain size effect. Ion track radii tend to saturate and even decrease at high electron stopping powers (>30 keV/nm) due to the velocity effect. The threshold electronic energy loss to form amorphous tracks in nanoclusters and large (>100 nm) crystals was estimated in the range 10.7–12.8 keV/nm. A strong size dependence was observed for smaller (<50 nm) isolated nanocrystals, with smaller crystals being significantly more sensitive to amorphous track formation.

Ion Tracks and Nanohillocks Created in Natural Zirconia Irradiated with Swift Heavy Ions

“…Another explanation for the absence of anisotropy is that the expulsion of molten matter is more significant in nanoparticle samples. In a recent study on nanoparticle Y2Ti2O7 [64], the isolated nanoparticles were more sensitive to SHI irradiation than larger samples, with an increasing susceptibility to track formation with a decreasing sample size. According to the literature, the higher sensitivity of nanoparticles can be explained by the presence of a surface upon which the expulsion of molten matter is significant.…”