Magnetic and Microstructure Study of Thin Films of FeCuNbMoSiB FINEMET Alloy

Thin films of FeCuNbMoSiB have been sputtered on Corning glass substrates with thicknesses varying from 10 to 200 nm with post annealing at 450 °C and 550 °C. Annealing in the presence of the magnetic field applied along the plane of a substrate develops an uniaxial magnetic anisotropy with the in-plane easy axis. Estimation of the effective anisotropy constant from the magnetization measurements gave Keff = 3.23 kJ/m3. Structure and surface of the films were investigated with the X-ray powder diffraction (XRD), resistivity measurements, and Raman spectroscopy. XRD and resistivity analyses show that thermal annealing at 550 °C improves the crystalline fraction and Fe-Si grain size. Raman spectra identified hematite, goethite, magnetite, as well as graphite contamination of film surfaces.