Layered structure of epitaxial yttrium iron garnet films

The layered structure of yttrium iron garnet films, ranging in thickness from 0.7 to 4.1 μm, grown epitaxially on single-crystal gallium-gadolinium garnet substrates, was investigated by x-ray spectral microanalysis. The ferrite films were chemically etched layer by layer in a mixture of orthophosphoric and sulfuric acids at T=353–423 K. It was established that the chemical composition of the films varies over the thickness because of the nonuniform distribution of gadolinium, gallium, lead, and platinum ions; the film-substrate transitional layer and the surface layer of the film differ most greatly with respect to the composition and magnetic properties. It was shown that the thickness of the transitional layers and their negative effect on the magnetic characteristics of ferrite films decrease appreciably if at the time of immersion of the substrate and pulling of epitaxial structure out of the fluxed solution the substrate holder together with a special mixer rotate at a rate of 50 rpm and the pulling velocity is 20 cm/min.