The influence of high-energy (3.5 MeV) electron irradiation on magneti
c and magneto-optical properties of YIG-based epitaxial films are stud
ied. The Faraday rotation at 0.63 mu m was found to decrease in Ga-sub
stituted films that may be connected with the process of radiation def
ects formation. The origin of observed property changes is discussed b
y examining the possibility of substituting displacements causing the
redistribution of Ga ions.