Change of permeability in amorphous ferromagnetic ribbons by heat treatment

The initial permeability μithe loss factor and the disaccommodation of non magnetostrictive Fe5Co70Si15B10and high magnetostrictive Fe78Si10B12and Fe80P13C7amorphous ribbons were measured as a function of temperature in the high frequency region. The initial permeability of as-prepared Fe5Co70Si15B10ribbon was observed to have maxima at about -50°C and just below the Curie temperature, and a minimum at about 280°C. For as-prepared Fe80P13C7ribbon, the permeability was almost independent of temperature from room temperature to about 230°C. The largest disaccommodation was observed at about 70°C for Fe5Co70Si15B10, and was not observed above 180°C.