Electronic structure and phase composition of silicon oxide in the metal-containing composite layers of a [(Co₄₀Fe₄₀B₂₀)₃₄(SiO₂)₆₆/C]₄₆ multilayer amorphous nanostructure with carbon interlayers

A [(Co₄₀Fe₄₀B₂₀)₃₄(SiO₂)₆₆/C]₄₆ multilayer amorphous nanostructure, consisting of alternating metal-containing composite layers and carbon interlayers, has been grown on a rotating glass-ceramic substrate by ion-beam-sputtering two targets, one of which had the form of a metallic plate of the Co₄₀Fe₄₀B₂₀ alloy with quartz inserts. The nonmetallic interlayers were grown by sputtering graphite (second target). In the multilayer nanostructure (MNS), the thickness (~4–8 nm) of the bilayers, consisting of the (Co₄₀Fe₄₀B₂₀)₃₄(SiO₂)₆₆ metal- and silicon oxide-containing composite layers and nonmetallic carbon interlayers, was determined by small-angle X-ray diffraction. Experimental data obtained by nondestructive depth profiling of the MNS using ultrasoft X-ray emission spectroscopy of the (Co₄₀Fe₄₀B₂₀)₃₄(SiO₂)₆₆ composite layers demonstrate that the composition of the dielectric component of the composite deviates from the stoichiometry of the quartz in the sputter target toward lower oxygen content, leading to the formation of the SiO_1.7 suboxide. Fitting Si L_2,3 spectra with reference spectra of known phases indicates that the content of the silicon suboxide phase in the composition of the composite layers can reach half of the composition of the dielectric component, with the second half being SiO₂. This circumstance can be favorable for increasing the role of a second carrier transport channel (granule–interlayer–granule) and contribute to the previously observed sharp drop in the resistivity and the overall rise in the magnetic permeability of the MNS.