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The effect of non-uniform quenching on the surface domain structure of amorphous Fe-based microwires
The magnetic domain structure of amorphous Fe77.5Si7.5B15 microwires was investigated by magnetic force microscopy. The diameter of the metallic part was 20 µm. It was found that the surface domain layer of uncoated microwires with positive magnetostriction could be divided into two regions: a region containing magnetic domains inclined to the axis or zigzag-shaped domains and a region containing ring domains with a radial orientation of the magnetic moment. It was assumed that that was due to stresses non-uniformly distributed across the cross-section and length of the microwire. The surface domain structure of the microwire was studied after removing the surface part with a thickness of 2 µm. The removal of the surface part resulted in the formation of a magnetic structure that did not have radial components of magnetic stray fields near the sample. When a magnetic field was applied (as in the case of the as-prepared microwires), a stable structure of ring domains with a width of 2.5–5 µm was formed.