Spin Relaxation in Mössbauer Spectra of Magnetically Ordered Systems

Abstract
A general formula has been derived for Mössbauer absorption spectra of magnetically ordered systems in the presence of electron spin relaxation. The calculation is independent of any particular model of the magnetic spin system and the result is expressed in terms of magnetic spin correlation functions. The leading nonvanishing terms describing line broadening due to spin fluctuations are evaluated explicitly, and a relatively simple result is obtained for the special case of a scalar spin-spin interaction. Line shapes are in general complex, but can display Lorentzian or Gaussian behavior in certain cases.