Magnetic properties of Fe-based glass-coated microwires

Axial hysteresis loops of glass-coated amorphous Fe70B15Si10C5 microwire have been measured as a function of both the diameter of metallic nucleus (from 3.7-14.9 mu m) and the thickness of the coating (4.0-9.6 mu m). They exhibit low-field rectangular hysteresis loops with a single and large Barkhausen jump even for samples as short as 5 mm long. Coercivity remarkably increases (roughly from 1 to 10 Oe) and remanence decreases (from 1 to 0.45 T), respectively, as the ratio of metallic nucleus radius to the total radius of the wire decreases from 0.63 to 0.16. The strength of the internal stresses induced during the fabrication depends on this ratio, and the easy axes of the corresponding magnetoelastic anisotropies determine the actual value of coercivity and remanence for these microwires.