CLUSTERS OF NATIVE POINT-DEFECTS AND HIGH-COERCIVE STATE IN FILMS OF CA,GE-SUBSTITUTED MAGNETIC GARNET

The method of X-ray diffuse scattering (XDS) is used to characterize t he point defect structure in epitaxial films of Ca,Ge-substituted magn etic garnet showing a high level of coercivity. It has been discovered that a high-coercive state is induced by clusters of ionic vacancies. The geometrical parameters and concentration of microdefects were obt ained by fitting the XDS intensity profiles calculated for model micro defects to the experimental triple-crystal rocking curves. The origin of point defect clusters in the calcium-rich Ca,Ge-substituted garnet is discussed.