Structure, Electronic Spectra, and Magnetic and Conductive Properties of Composite Films (CoFeB + SiO2)

The paper studies the magnetic structure, electronic spectra, magnetic and conductive properties of composite films (CoFeB + SiO2) with different metal concentrations CoFe x = 41‒75 at %. It is shown that the structure of the composite films changes with increasing x from a granular structure at x = 41, 42 at % to a granular-percolation structure at x = 47‒55 at %. At x = 60‒70 at %, the films have a stripe and labyrinthine magnetic structure, for which the band width increases with increasing x. The paper studies the effect of the concentration x of the composite films and the type of magnetic structure on the electronic spectra at binding energies up to 1.5 keV, obtained by X-ray photoelectron spectroscopy (XPS) at room temperature. It has been shown that the height (concentration of ejected electrons) and area of the electron peaks of Co2p, Fe2p, B1s, Si2p, O1s are strongly influenced by the concentration x and magnetic structure. The heights and areas of the peaks of the intensity of the electron states of the film surface obtained by XPS can become one of the key parameters for controlling the structure of composite metal-dielectric films obtained by ion-beam sputtering. It has been shown that the magnetization, coercivity, electrical resistance, and magnetoresistance of composite films are determined by the concentration x and the magnetic structure of the composite films. It has been shown that the highest absolute magnetoresistance and maximum sensitivity to static magnetic fields belong to composite films (CoFeB + SiO2) with a granular structure at x = 41 at %.