Effect of annealing field orientation on complex permeability spectra in Co-based amorphous ribbon

Abstract We prepare field-annealed amorphous magnetic ribbons of Co 66 Fe 4 NiB 14 Si 15 at various angles, α , to the ribbon axis. The reversible and irreversible relaxation dispersions are decomposed from the complex permeability spectra in the frequency range of 1 kHz–10 MHz. Static permeabilities and relaxation frequencies for the reversible and irreversible relaxations are determined from the decomposed spectra, respectively. The irreversible permeability decreases with α and becomes negligible for α =90 ∘ . The reversible permeability decreases as α increases for α ⩽30 ∘ , but increases for the further increase of α >70 ∘ . The relaxation frequency of irreversible relaxation shows a nearly constant value of 30 kHz for all samples. The relaxation frequency of reversible relaxation was 316 kHz for α ⩽70 ∘ and increases to 724 kHz for α =90 ∘ . The α dependence of the static permeabilities and relaxation times are analyzed in terms of the effect of easy-axis orientation on magnetization processes by domain wall motion and magnetization rotation.