Effect of Cu addition on nanocrystallization behaviors and magnetic properties of the Fe76.5−xC6.0Si3.3B5.5P8.7Cux (x = 0-3 at.%) bulk metallic glass

► Effect of Cu on the modification of primary phase of soft magnetic nanocrystalline alloys. ► Soft magnetic nanocrystalline alloys with amorphous precursor having high glass forming ability. ► Enhancement of glass forming ability with small amount of Cu addition.