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

Abstract

We prepare field-annealed amorphous magnetic ribbons of Co 66Fe 4NiB 14Si 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.