Fabrication and characterization of magnetostrictive amorphous FeGaSiB thin films

In this work, amorphous FeSiB and FeGaSiB thin films have been fabricated on silicon substrates using a co-sputtering-evaporation deposition technique. The effect of adding gallium into FeSiB (Metglas) thin films on the structure, magnetic properties and magnetostriction have been studied. From X-ray diffraction (XRD), all the films were amorphous and the observed peaks were for the Si substrate. X-ray Photoelectron Spectroscopy (XPS) measurements were carried out to determine the film's composition, which was found to be Fe83Ga11Si5.2 B0.8. Atomic force microscopy (AFM) images were taken to measure the film thickness along with studying the surface topography. It was found that the film surface had an average roughness of 0.461 nm. For both FeSiB and FeGaSiB thin films, the effect of the thickness of the films on the magnetic properties and magnetostriction were investigated. The results showed that adding Ga into the FeSiB films changed the magnetic properties by reducing the saturation induction along with changing the magnetic anisotropy from uniaxial to isotropic. For the FeGaSiB films, the coercive field decreased and the saturation field (Hs) increased with film thickness. The magnetostriction constants of the FeGaSiB films were all larger than the FeSiB films for thicknesses greater than 40 nm.