Description in a local model of the magnetic field distributions of Fe1-xNix disordered alloys

A local model based on the idea of atoms distributed within a crystalline lattice and following a binomial probability method for describing the hyperfine field distributions obtained from the room temperature Mossbauer spectra of the disordered Fe-Ni system is presented. This model allows one to calculate the mean hyperfine field for each concentration from 5 to 95 at. % Ni, to determine what are the most probable sites and to interpret why the mean hyperfine field initially increases and then decreases with the Ni concentration in the BCC phase. The results are in good agreement with the experimental results except for Invar composition and for 85 at. % Ni which demand a different treatment. (C) 1997 American Institute of Physics.