It was recalled that, although 57Fe Mössbauer spectroscopy was a particularly suitable method for the characterization of nano-structured solids, attempts to isolate spectral features that could be associated with grain boundaries encountered unexpected difficulties in the case of ball-milled or mechanically alloyed metallic materials. The example of Ag-Fe alloys prepared by mechanical alloying was discussed here in order to show what kind of structural information could be extracted from hyperfine parameters in spite of the presence of large concentrations of lattice defects and long-range magnetic interactions.

The Difficulty of Isolating Grain Boundary Components in the Mössbauer Spectra of Ball-Milled Materials - Iron and Silver–Iron Alloys. G.Rixecker: Solid State Communications, 2002, 122[6], 299-302