On the Formation of Microheterogeneities in Epitaxial Films of Nonstoichiometric Ferrogarnets

Abstract

The mechanisms of microinhomogeneity formation in epitaxial films with negative (\(\varepsilon < 0\)) and positive (\(\varepsilon > 0\)) values for the mismatch of the film and substrate lattice periods are considered. It is shown that at annealing temperatures up to 1100°C the lattice parameter barely changes and there are regions enriched with cation and anion vacancies at the boundary of inclusions. It is established that the share of the volume occupied by microinhomogeneities is determined by the parameter of nonstoichiometry \(\gamma ,\) which can be distributed unevenly. It is shown that the formation of defects in the oxidation process is more active than in the case of reduction. The possibility of the existence of a concentration gradient of Fe⁴⁺ ions in the film thickness is established. The efficiency of the violation of coherence of matching the imperfect region with the matrix and stress relief by the diffusion of vacancies to the interface is proved.