The variation of the domain wall pinning strength with the depth within the Co74Fe6B20 amorphous alloy

The derivative of magnetization with respect to time (dM/dt) vs. the applied field (H) curves for as-quenched Co74Fe6B20 amorphous alloy have been investigated. The effect of etching of a particular surface of the sample on the dM/dt vs. H curve, with dc current passing through the sample, was studied. It was shown that the domain wall pinning strength depends strongly on the depth within the sample, the variation being particularly strong close to the ribbon surfaces. The measurements with dc current confirm our previous assumption about the pinning inhomogeneity (PI) in this sample and suggest that PI may be inherent to the melt-spun amorphous ferromagnets. (orig.)