Yaremiy I. Defects in the structure of the subsurface layers of ion-implanted epitaxial films and single crystals of garnet.

Defect structure of ion-implanted subsurface layers of gadolinium gallium garnet single crystals and epitaxial ferrite-garnet films was investigated in the dissertation work. Modification of the materials was carried out by Не+, В+, N+, F+ ions. It was shown that the formation of dislocation loops by the point radiation defects association in the ion-implanted subsurface layers of the investigated materials occurs only in parallel to the sample surface planes. For correct analysis of the system of defects within the statistical dynamical theory the functional dependencies were derived and the values of structurally sensitive to defects X-ray parameters were calculated taking into account the effects of anisotropy in the orientation of dislocation loops. The information about structure and characteristics of defects in unimplanted and implanted single crystals and films was obtained. The relationships between the characteristics of defects and the parameters of magnetic microstructure of the investigated materials were found. It was shown that the state of grown on gadolinium-gallium garnet substrates films is totally strained. Point defects and dislocation loops with an average size of 30 - 70 ? mainly formed in the subsurface layers during ion implantation. With radiation dose increasing the concentration of the dislocation loops increases and their radius decreases. The ion-implanted subsurface layer in the parallel to the crystal surface plane is totally strained, despite the large value (to 3%) of relative deformation in perpendicular to the crystal surface plane direction.