Nanocrystallization processes and reorientation of the magnetic moments of FeCuNbSiB films

The investigation of the nanocrystallization and magnetic properties of FeCuNbSiB films by X-ray diffraction (XRD) and Mössbauer spectrum is presented in this paper. The XRD results showed that the films begin to crystallize at 400°C. The nanocrystalline volume fraction of the samples and the orientation of the magnetic moments could be obtained by the Mössbauer spectrum. From as-deposited state to the sample annealed at 570°C, the magnetic moments of the films were orientated from the initial direction parallel to the film plane to the direction perpendicular to it, and later back. Eventually, moments orientations of the film samples were random. The magnetic studies also revealed the moments orientations during the heat treatment. The giant magneto-impedance (GMI) ratio of sandwiched films varies with changing orientation of magnetic moments. When the orientation of moments was perpendicular to the film plane, the GMI ratio decreased dramatically.