MAGNETIZATION PROCESSES IN METALLIC GLASSES FOR FLUXGATE SENSORS

Magnetization processes for two cores prepared with Co66.5Fe3.5Si12B18 metallic glass ribbons in the as-quenched and stress-annealed states have been studied. Employing both cores as sensitive sensors in a fluxgate magnetometer, low rms noise levels (similar to 12 pT) are achieved for the stress-annealed ribbon core and 85 pT rms for the as-quenched one, in the 0.06-10.0 Hz frequency range. The influence of different biasing fields on circumferential conmutation curves and permeabilities increasing the excitation field on both cores allows to distinguish their magnetization processes. The predominance of coherent rotations in the stress-annealed ribbon core explains the reduction of the Barkhausen noise as compared to the as-quenched one, mainly with domain wall displacement processes.