Investigation of surface micromagnetic structure of FeCuNbSiB amorphous microwires

Abstract The study of local magnetic properties at the surface of the as-cast and annealed, at 550°C for 1 h Fe73.5Cu1Nb3Si13.5B9 amorphous microwire with a magnetic core of 10 μm diameter was carried out using scanning Kerr microscopy. The as-cast microwires had an amorphous state and the annealed samples exhibited ultra-fine structure with the grain size of 10–12 nm. The as-cast microwires were discovered to have the strong inhomogeneity of the near-surface magnetic properties that was explained by the dispersion of the magnetic anisotropy. The annealed microwires were found to have the nanocrystalline phase formation that leads to an improvement of their soft magnetic properties and a significant increase in the homogeneity of magnetic characteristics.