Properties of micromagnetic structures in amorphous FeCuNbSiB alloys

Results are presented of a magnetooptic investigation of the surface microm agnetic structure of FeCuNbSiB ribbons in the initial state and after annea ling at 550 degrees C for 1 h. In the initial state the samples were amorph ous, whereas after annealing they exhibited a nanocrystalline structure wit h typical grain sizes of 10-12 nm. Dispersion of the magnetic anisotropy wa s observed in the samples studied; this was responsible for the nonuniformi ty of their local magnetic properties. It was found that the linear dimensi on of the magnetic inhomogeneities in the initial and annealed samples was 120-150 and 50-70 mu m, respectively. (C) 1999 American Institute of Physic s. [S1063-7850(99)01101- 5].