Mössbauer spectra of Stoner-Wohlfarth particles in rf fields in a modified relaxation model

A theory of Mössbauer absorption spectra in the presence of external rf fields is developed for Stoner-Wohlfarth particles in an extended relaxation model with a more realistic description of the relaxation process. Calculating in this model, we track the transformation of the Mössbauer spectra as a function of relaxation processes for the transitional region and frequencies and amplitudes of the rf field where the well-resolved hyperfine structure transitions into an isolated central peak with satellites. In this transitional region new types of resonance effects are found which have no analogy with previously known resonance phenomena.