Studies of thermal and magnetic properties of Fe-based amorphous and nanocrystalline glass coated microwires

We studied the influence of magnetoelastic energy on properties of nanostructured glass-coated microwires with soft magnetic behaviour (Finemet-type microwires of Fe70.8Cu1Nb3.1Si14.5B10.6 and Fe73.8Cu1Nb3.1Si13B9.1 compositions). The magnetoelastic energy, stored during the Finemet-type microwires fabrication, affected the hysteresis loops, coercivity and heat capacity of Finemet-type microwires. Hysteresis loops of all as-prepared microwires showed rectangular shape, typical for Fe-rich microwires. As expected, coercivity, HC, of as-prepared microwires increases with decreasing of the ratio ρ defined as the ratio between the metallic nucleus-diameter, d to total microwire diameter, D. On the other hand, the change of heat capacity in TC, ΔСр, exhibits increasing with the ratio ρ. This relationship holds for microwires in the as-prepared state as well as after annealing.