MAGNETIC-FIELD-INDUCED ANISOTROPY IN NANOCYRSTALLINE FE-CU-NB-SI-B ALLOYS

Magnetic field annealing of nanocrystallized glassy Fe-Cu-Nb-Si-B alloys induces an uniaxial anisotropy, the easy axis being parallel to the direction of the applied field. The induced anisotropy energy, K(u), reaches an equilibrium value characteristic of the individual alloy composition if the magnetic field is applied during the formation of the nanocrystalline state. The typical range of magnitude of the induced anisotropy energy is K(u) = 10-100 J/m3. The analysis of the experimental data suggests that the anisotropy is induced mainly in the precipitated bcc FeSi grains and that its magnitude is determined by the fraction and the Si content of the crystallites.