The effect of magnetic field annealing on magnetic properties in ultrathin Fe-based nanocrystalline alloys

Ultrathin [Fe.sub.78][Al.sub.4][B.sub.12][Nb.sub.5][Cu.sub.1] and [Fe.sub.83][B.sub.9][Nb.sub.7][Cu.sub.1] nanocrystalline ribbon alloys below 10 [[micro]meter] in thickness were annealed in transverse magnetic field, and then the high-frequency soft magnetic properties and their compositional effect were investigated. Very high effective permeability and .excellent magnetic core loss characteristics in MHz range were obtained for both alloys after optimum annealing. However, the Al-added alloy was more sensitive to the magnetic field annealing and much improved soft magnetic properties in the high frequency range were revealed.