  Iron self-diffusion in nano-composite FeZr alloy has been investigated using
neutron reflectometry technique as a function of applied compressive stress. A
composite target of (Fe+Zr) and (57Fe+Zr) was alternatively sputtered to
deposit chemically homogeneous multilayer (CHM) structure,
[Fe75Zr25/57Fe75Zr25]10. The multilayers were deposited on to a bent Si wafer
using a 3-point bending device. Post-deposition, the bending of the substrate
was released which results in an applied compressive stress on to the
multilayer. In the as-deposited state, the alloy multilayer forms an amorphous
phase, which crystallizes into a nano-composite phase when heated at 373 K.
Bragg peaks due to isotopic contrast were observed from CHM, when measured by
neutron reflectivity, while x-ray reflectivity showed a pattern corresponding
to a single layer. Self-diffusion of iron was measured with the decay of the
intensities at the Bragg peaks in the neutron reflectivity pattern after
thermal annealing at different temperatures. It was found that the
self-diffusion of iron slows down with an increase in the strength of applied
compressive stress.
