Description in a local model of the magnetic field distributions of mechanically alloyed Fe-Si (3.5 wt%)

A local model based on the idea that the atoms are distributed within a cry stalline lattice, following a binomial probability method for describing th e hyperfine field distribution (HFD) obtained from room temperature Mossbau er spectra is presented. It is applied to disordered, 3.5 wt%, Fe-Si mechan ically alloyed during 15, 30, 50 and 75 h. This model also permits, through a fitting parameter, to evaluate the influence of the alloy milling time. The theoretical curves have fitted quite well with the experimental ones an d the fitting parameters show that, in agreement with the experimental data , when each silicon atom substitutes an iron atom in the nearest neighborho od, an approximately 3 T diminishment in the hyperfine field is presented. This model also allows us to conclude that the presence of silicon atoms in the next nearest neighborhood have practically no influence in the hyperfi ne field, because its representative parameter fits for these alloys with a zero value.