Moessbauer effect and short-range order in Fe-P-B and Fe-P-C amorphous alloys

The hyperfine field of some amorphous iron-based alloys (Fe-P-B, Fe80B20, and Fe75P15C10) obtained by 'splat cooling' is investigated. The isomer shift can be interpreted either in terms of the electron transfer from the metalloid to iron 'd'-bands, or in terms of the change in the 's'-electron density. The experimental spectra are fitted according to two procedures, by assuming, respectively, a continuous and discrete distribution of hyperfine fields. These methods yield distributions which have approximately the same shape and the same average hyperfine field. Such a shape can be related to local environments which are similar, on an average, to the crystalline counterpart. The average hyperfine field values and the observed magnetic moment suggest that the distribution around the nucleus is constant for the alloys investigated. On the other hand, it is similar to those of various crystalline compounds of transition metals and metalloids. (author)