Fi40Ni40B20 metallic glass is a key material among the many amorphous systems investigated thus far, owing to its high strength and appealing soft magnetic properties that make it suitable for use as transformer cores. In this study, microfibers are fabricated down 5 µm diameter. Three different melt–spinning wheel velocities: ≈51 m s−1, ≈59 ≈63 s−1 (MG1, MG2, MG3) used. Their fully structure c...