XANES and USXES investigations of interatomic interaction at the grain boundaries in nanocomposites (Co41Fe39B20)x(SiO2)1-x

Interatomic interaction in amorphous (Co41Fe39B20)(x)(SiO2)(1-x) nanocomposites was investigated with the use of X-ray absorption near-edge structure (XANES) technique that is one of the most sensitive to the chemical surrounding of the elements in multi-component compounds. XANES spectra of Fe L-2,L-3-edges, Co L-2,L-3-edges, B K-edge, Si L-2,L-3-edges and O K-edge demonstrated the presence of interatomic interaction between the elements of metallic and dielectric components of the nanocomposite. These interactions result in a formation of the complex multiphase system and its electron structure should have an influence on the electrophysical and magnetic properties of nanocomposites. Particularly, transformation of the fine structure of iron L-2,L-3-edges spectra represents the change of ratio of two- and three-valence iron atoms in oxides and/or silicates. The presence of CoO and complex boron oxides in nanocomposites was also detected. Therefore, electroconductivity within the boundaries of a single grain of nanocomposite (nanoferrite) with a possible composition of FeO.Fe2O3.CoO.BxOy is due to the transitions of electrons not only between Fe2+ and Fe3+ ions but also between the ions of Co2+, Fe2+ and Fe3+. At the same time, dielectric component represents a mixture of silicon oxide and silicates of transition metals. (c) 2006 Elsevier B.V. All rights reserved.