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

Magnetic field annealing of nanocrystallized glassy Fe-Cu-Nb-Si-B alloys induces a 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. Typical magnitudes of induced anisotropy energy range from about K(u) = 10 J m-3 to K(u) = 100 J m-3. Analysis of the experimental data suggests that the anisotropy is mainly induced in the precipitated b.c.c. FeSi grains and that its magnitude is determined by the fraction and silicon content of crystallites.