CURRENT ANNEALING AND MAGNETOIMPEDANCE IN COFEBSI AMORPHOUS RIBBONS

CoFeBSi amorphous ribbons were current-annealed at 600 mA for times ra nging from 9 sec to 5 min. Their complex impedance response was measur ed in the frequency range 5 Hz-13 MHz, under a DC field of zero and at 6.3 kA/m. Transverse permeability (and therefore magnetoimpedance) sh owed a maximum for an annealing time of similar to 1 min, while the pr opagating field (or unpinning field) for transverse domain walls, exhi bited a minimum for the same annealing time, These results show the di rect dependence of magnetoimpedance on transverse induced anisotropy, and are interpreted in terms of the dependence of the latter on two co mpeting configurations.