Effect of Co and Ge addition on soft magnetic properties of Fe–Zr–B–Cu alloys

Abstract Microstructure and magnetic properties are studied for Fe 78 Co 5 Zr 6 Ge 5 B 5 Cu 1 alloy. Curie temperature of the amorphous phase is increased by 200 K with respect to Fe–Zr–B–Ge–Cu alloys, without losing the ultrasoft magnetic properties exhibited at room temperature ( H C ∼10 A/m). Nanocrystalline microstructure shows a high crystalline volume fraction of α-Fe nanocrystals (∼0.85) with size below 13 nm. Ge content in the crystalline phase is found to decrease continuously during nanocrystallization.