Effects of Annealing on Magnetic Properties of Amorphous and Nano crystal line (Fe0.5Co0.5)73.5Cu1Nb3Si13.5B9 Wires

Amorphous (Fe0.5Co0.5)(73.5)Cu1Nb3Si13.5B9 wires were submitted to the thermal treatment of Joule-heating at current (j(alpha) = 26 - 45.5 A/mm(2)) and time(t = 20 - 600s). The effects of annealing on the magnetic properties has been investigated in order to improve the soft magnetic properties by the measurements of longitudinal hysteresis loop and the circular permeability, mu = mu ' - j mu '', determined from the measurements of impedance, Z = R + jX, as functions of frequency (f = 10 - 10(5) Hz). We found that the most outstanding soft magnetic properties were observed in samples annealed at j(alpha) = 32 - 36 A/mm(2) for 20 s due to the nanocrystallization. On the other hand, all samples exhibit the relaxation-type feature of permeability spectrum. In addition, from the changes of circular permeability with the annealing time, we can conclude that the optimum annealing condition to acquire best magnetic soft properties is a longer or a shorter time for the amorphous or the nanocrystalline alloy, respectively.