Mössbauer spectroscopic studies of defect structure and alloying effects in nanostructured materials

Abstract

Mossbauer spectroscopy provides spectral information from both ordered and structurally disordered regions of a solid and is therefore well suited for the atomic-scale characterisation of materials with very high defect concentrations. This applies especially to nanocrystalline materials where 5–50% of the atoms may be located at planar defects such as grain boundaries. In this paper, the range of Mossbauer spectroscopy in exploring the structure of nanostructured materials will be discussed in the form of case studies dealing with (i) nanometer-sized antiphase domains in the intermetallic compound Fe3−x Si1+x , (ii) ball-milling induced structural changes and alloying effects in dilute Al(57Fe) and Y(57Fe) alloys, and (iii) the Mossbauer signature of grain boundaries in nanocrystalline W(57Fe).