Spivak V. Influence of external variable magnetic field on the shape of Mossbauer spectrum of soft ferromagnets

In the thesis a general theory is developed for Mossbauer absorption by soft ferromagnets exposed to fadio-frequency (rf) magnetic field, taking into account both step-wise reversals of the magnetic field at the nuclei and their forced vibrations. Special attention has been paid to the case, when periodic reversals of the rf field and forced vibrations are coherent to each other. Theory has been extended also to the case, when both a rf field and a constant one, being parallel, are applied to soft ferromagnet. We suggested an asymmetric step-wise reversals model to describe such experiments. The dynamical scattering theory has been build for transmitting of gamma -rays through a soft ferromagnet in rf field. The frequency spectrum of transmitted radiation is found to consist of equidistant lines spaced by twice the rf frequency.