On the Effect of Magnetic Pulsed Treatment on the Surface Structure and Magnetic Properties of Tape Amorphous Alloys Fe(Ni, Cu)(SiB)

Abstract

The methods of scanning electron, atomic force, and magnetic force microscopy, together with measurements of the magnetic characteristics before and after exposure to pulses of a weak magnetic field (10–100 kA/m) of low frequency (10–20 Hz), were used to study the features of the surface state that determine the domain structure, magnetic properties and magnetic losses during magnetization reversal of ribbon amorphous Fe(Ni, Cu)(SiB) alloys obtained by ultrafast cooling by melt spraying on a rotating drum. Both surfaces of the foils were studied: the surfaces of the samples adjacent to the copper drum, which had an inhomogeneous structure characteristic of all rapidly quenched samples, and other sides of the foils, the surfaces of which were more even, which made them look shiny. When studying the surfaces of foils by atomic force microscopy after their magnetic pulse processing, no changes in the nature of the surface structure were found. The changes were recorded on the images of the shiny side of the samples by magnetic force microscopy. If no domain structure was observed before magnetic pulse treatment, then after magnetic pulse treatment, stripe domains with a width of 0.6–0.8 nm and closing domains with a width of 1.0–1.6 nm were found on structural defects, and in some areas of the surface, along with this, a weak magnetic contrast in the form of large and small domains with a shape close to triangular. It has been established that the magnetization reversal losses are largely related to the losses caused by eddy currents and are related to the domain width (about 1.5 nm), which depends only slightly on the modes of magnetic pulse processing. The obtained research results can be used to refine the technique for relieving stresses arising in the process of manufacturing amorphous ribbons.