  The investigation of devitrification in thermally annealed nanodimensional
glassy alloy thin films provides a comprehensive understanding of their thermal
stability, which can be used to explore potential applications. The amorphous
to crystalline polymorphous transformation of cosputtered NiZr alloy (Ni78Zr22
at%) films, with a thickness lower than the reported critical limit of
devitrification, was studied through detailed structural characterization and
molecular dynamics (MD) simulations. Devitrification to a nanocrystalline state
(Ni7Zr2 structure) was observed at 800 degC, with an increase in density
(approx 3.6%) much higher than that achieved in bulk alloys. Variation in the
magnetic property of the films and the overall physical structure including
morphology and composition were examined before and after annealing. MD
simulations were employed to effectively elucidate not only the high
densification but also the increased magnetic moment after annealing, which was
correlated with the simulated change in the coordination number around Ni
atoms. The structural relaxation process accompanying devitrification was
described as a disorder-to-order transformation while highlighting the crucial
role played by chemical short range order prevalent in glassy materials.
