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

Amorphous Fe-Cu-Nb-Si-B ribbons have been nanocrystallized under tensile stress applied along the ribbon axis. This results in a strong magnetic, creep-induced anisotropy with an easy ribbon axis for low and, a hard ribbon axis for high Si-concentrations, respectively. The analysis of the compositional dependence shows that the anisotropy energy correlates linearly with the saturation magnetostriction of the precipitated bcc-FeSi grains. it is therefore proposed that the induced anisotropy mainly originates from the magneto-elastic anisotropy of the bcc grains due tensile back stresses exerted by the anelastically deformed amorphous matrix.