Magnetic properties of Co-based amorphous alloys annealed with magnetic field transverse to the ribbon axis

The effect of transverse magnetic field annealing on the magnetic properties, in particular initial permeability (μ´), was studied for nonmagnetostrictive Co-based amorphous alloys with various Curie temperatures. Extremely high magnetic permeability was attained for the samples with Curie temperature below 240°C. For example, μ´ measured at 1 kHz and 2 mOe is 200000. Low magnetic core loss at high frequency was also obtained. The results were discussed in terms of the transverse magnetic anisotropy induced by the magnetic field annealing. There is an inverse linear relation between initial permeability and the transverse anisotropy. Extremely high permeability was obtained for small transverse anisotropy, below 10 erg/cc.