  Materials are subjected to energetic particles in a number of radiation
environments,and are hence prone to undesirable (radiation) damage.We report
here the superiority of the nanocrystalline phase over bulk for radiation
tolerance under simultaneous irradiation with high energy (electronic energy
loss (Se) dominant) and low energy (nuclear energy loss (Sn) dominant)
particles.Nano-crystalline yttria stabilized zirconia is found to exhibit
lesser radiation damage (viz.degradation in crystallinity),when compared to its
bulklike counterpart,against simultaneous irradiation with high energy 27 MeV
Fe and low energy 900 keV I ions.This is interpreted within the framework of
the thermal spike model after considering (i) the fact that there is
essentially no spatial and time overlap between the damage events of the two
simultaneous ion beams,and (ii) the influence of grain size on the radiation
damage against separate Sn and Se.The present work besides being of keen
interest for fundamental understanding of ion material interactions,also paves
the way for the potential application of nanocrystalline materials in the
nuclear industry where such simultaneous irradiations are encountered.
