Measurements of diffusional Mössbauer line broadening in monocrystalline samples at high temperatures provided microscopic information concerning atomic jumps. It was possible to separate the jumps of Fe atoms between the various sub-lattices of Fe-Si intermetallic alloys with the D03 structure, and to measure their frequencies. The diffusion of Fe in Fe-Si samples with Fe concentrations of between 75 and 82at% revealed a marked compositional dependence. That is, the jump frequency and the relative proportions of jumps on Fe sub-lattices and into anti-structural (Si) sub-lattice positions changed markedly. When close to the stoichiometric Fe3Si composition, the Fe diffusivity was extremely high, and jumps occurred exclusively between the three Fe sub-lattices.

B.Sepiol, G.Vogl: Hyperfine Interactions, 1995, 95[1-4], 149-59