Improvement of soft magnetic properties in Fe38Co38Mo8B15Cu amorphous and nanocrystalline alloys by heat treatment in external magnetic field

The influence of both longitudinal and transverse magnetic field applied during heat treatment on the soft magnetic behavior in the amorphous and nanocrystalline Fe38Co38Mo8B15Cu alloys has been investigated. Sheared loops with good field linearity were achieved after annealing in transverse magnetic field. The value of induced anisotropy constant Ku after such annealing increased from 440 J/m3 for thermally relaxed amorphous samples up to 935 J/m3 for alloys in advanced stage of primary crystallization. The nanocrystallization under a presence of the longitudinal magnetic field results in squared hysteresis loops that are characterized by reduction of coercivity Hc to 3–7 A/m. Such low Hc values surpass those previously reported for FeCo-based nanocrystalline alloys.