Structural and magnetic transformations in Y3Fe5O12 under neutron irradiation

Samples of yttrium iron garnet (YIG) irradiated by fluences of fast neutrons (0 to 3x1024 m-2) are investigated by X-ray, neutron diffraction, and magnetic methods. It is shown that irradiated samples have spatial-inhomogeneous structure characterized by the presence of microregions of the initial crystal, amorphous and defected phases. The coexistence of these interacting microregions, which relative concentrations vary depending on fluence, is responsible for magnetic transformations observed in YIG under irradiation. It is shown that the observed regularities of radiation transformations may be explained in terms of the continuum percolation theory. (orig.)