Mössbauer Spectra in Fe–Ni Invar Alloys

Abstract

Mössbauer spectra of Fe–Ni Invar alloys are calculated by means of the mixture model of the ferromagnetic and paramagnetic phases proposed before in the itinerant electron model. Gaussian distribution of the effective fields to Fe⁵⁷ nucleus is assumed. It is shown that the calculated spectra agree well with the observed ones. The origin of the distribution of the effective fields is discussed in terms of the environment of Fe⁵⁷ atom, spin fluctuations and the relaxation process of itinerant electron spins. It is shown that this model can explain the observed Mössbauer spectra in Fe–Ni Invar alloys.