Annealing effect on domain wall motion and magnetization rotation in amorphous Fe₈₄Zr₇B₈Cu₁ ribbons

The frequency spectra of complex permeability have been measured as a function of ac field amplitude in the annealed amorphous Fe₈₄ Zr₇B₈Cu₁ ribbons. The longitudinal permeability results from the rotational magnetization for small ac field, h₀<23.4 mOe in as-quenched sample. However, for h₀⩾23.4 mOe, the wall motion begins to be involved in the low frequency region. The permeability due to the wall motion drastically decreases with increasing annealing temperature, while the permeability due to the rotational magnetization increases with increasing annealing temperature up to 500°C and then decreases for higher annealing temperature