We consider two amorphous multilayer nanostructures (MLNS) [(Co 45 Fe 45 Zr 10 )/a-Si: H] 41 -I and [(Co 45 Fe 45 Zr 10 ) 35 (Al 2 O 3 ) 65 /a-Si:H] 41 -II that were obtained by ion-beam sputtering. For determination of the phase composition of the buried amorphous silicon interlayers in these MLNS, we used nondestructive ultrasoft X-ray emission spectroscopy technique (USXES). The use of the USXES enables to register the silicon Si L 2,3 -spectra providing the information about the local partial densities of Si s and d occupied states of silicon valence band in silicon-contained materials. According to the simulation and fitting procedure to the experimental data, Fe 3 Si and a small amount of oxide (SiO 2 :H) were found in the interlayer of MLNS-I. At the same time, the content of silicon dioxides (SiO 2 ) decrease from surface layers to the deep ones. On the other hand, simulation of the phase composition of MLNS-II reveals the presence of the silicides Fe 3 Si and Co 2 Si, oxides SiO 2 and SiO 1.3 , and a small amount of a-Si:H. The percentage of cobalt silicide Co 2 Si and suboxide SiO 1.3 increased in the deep layers of the MLNS-II. KEYWORDS interfaces, ion-beam sputtering, multilayer nanostructures, silicides of 3d metals, silicon oxides, ultrasoft X-ray emission spectroscopy

Interatomic interactions and superstructures of multilayer nanostructures (MLNS) consisting of ferromagnetic composite layers and silicon interlayers with or without hydrogen are studied here by means of X-ray diffraction (XRD), X-ray reflectivity (XRR), IR spectroscopy, and ultra-soft X-ray emission spectroscopy (USXES). The MLNS [(Co45Fe45Zr10)35(Al2O3)65/a-Si:H]100 and [(Co45Fe45Zr10)35(Al2O3)65/a-Si]120 were deposited on the substrate Si(100) by ion-beam sputtering of two targets, where the first target was a plate of Co45Fe45Zr10 alloy with Al2O3 inserts, and the second target was a single-crystal silicon. Our results show that the iron (FeSi2) and cobalt (CoSi, CoSi2) silicides are formed at the interfaces of the composite metal-containing layer/silicon interlayer. It is demonstrated that the metal clusters of composite layers and interface silicides are partially oxidized to form iron, cobalt, and silicon oxides together with zirconium silicate. Due to the formation of silicides at the interfaces, the composition of MLNS superstructures becomes more complex, and their periods are significantly reduced (down to 5–6 nm) compared to the nominal values of bilayers of about 6.9 nm.

We investigated the role of microstructure and In2O3/C interlayer thickness on the electrical transport properties of [(Co40Fe40B20)34(SiO2)66/(In2O3)/C]46 multilayers prepared using ion-beam sputtering. These multilayers were characterized using an X-ray diffraction, X-ray reflectivity, impedance spectroscopy, and magnetoresistive measurements. The X-ray diffraction data showed that regardless of the layer thickness, all components of the multilayers are X-ray amorphous. Fitting X-ray reflectivity data, multilayer periodicities are extracted and layers thicknesses, densities and roughnesses are determined. Impedance spectroscopy has shown a resistive-capacitive coupling between electrically conductive ferromagnetic CoFeB clusters which corresponds to the model of a prepercolation composite. For the thinnest multilayer with nonmagnetic In2O3/C interlayer thickness of about 1.6 nm, we managed to achieve a magnetoresistance of about 0.8% at room temperature and 3.2% at cryogenic temperature.

The multilayer nanostructures have drawn attention in fields from spintronics to microwave electronics. The purpose of this work was to determine the composition of individual layers and to control interfaces in three‐layer superstructures [(Co40Fe40B20)34(SiO2)66/ZnO/C]46 by means of X‐ray diffraction and X‐ray reflectivity. The samples with different thicknesses of metal‐containing composite layers together with zinc oxide and carbon interlayers were deposited on the glass substrate by ion‐beam sputtering of three targets, one of which was a composite (Co40Fe40B20)34(SiO2)66. X‐ray diffraction results showed the X‐ray amorphous state of the ferromagnetic metal clusters CoFeB, the dielectric matrix of silicon oxide SiO2, and carbon interlayers. However, the intermediate layers of the zinc oxide ZnO were found to have a nanocrystalline structure. The X‐ray reflectivity measurements indicate a good agreement between the experimental and nominal values of both the periods of three‐layer superstructures and the thicknesses of metal‐containing composite layers and interlayers.