Figure 1

Hysteresis loops of Fe-rich amorphous microwires. All the samples have the same length and different metallic nucleus diameter d and total diameters D: Fe₇₀B₁₅Si₁₀C₅ microwires with ρ = 0.63, d = 15 μm (a); μ = 0.48, d = 10.8 μm (b); μ = 0.26, d = 6 μm (c); μ = 0.16, d = 3 μm (d); and of Fe_72.75Co_2.25B₁₅Si₁₀ microwire with μ = 0.14, d ≈ 1.4 μm, D ≈ 10 μm (e).