Ferromagnetic Resonance of Amorphous Ribbons Fe78B13Si9

Changes in the ferromagnetic resonance field in amorphous Fe₇₈B₁₃Si₉ ribbons with surface polishing and annealing are reported. Grooves 5 μm or so deep in the surface tend to greatly affect the magnetic anisotropy, hence samples were polished with emery paper and by electrolysis and the FMR strength and anisotropy field H_u determined after each polishing. Such polishing led to a general decrease in the resonant field and in H_u. Annealing of polished samples at 400° in nitrogen was found to further reduce the FMR field, but had no effect on H_u.