Surface magnetic characterization of Fe-rich amorphous ribbons

Surface magnetic behavior of the as-cast Fe77.5Si7.5B15 amorphous ribbons was investigated using the longitudinal magneto-optical Kerr effect. The magnetic hysteresis loops were performed for the both ribbon surfaces, in contact with the quenching wheel and the other one (free side), with the external magnetic field parallel and perpendicular to the ribbons length. In the case of magnetic field parallel to the sample longitudinal axis, the coercive field for the ribbon side in contact with the quenching wheel (about 500 A/m) is higher than for the free side (about 250 A/m). The coercive field value (175 A/m) obtained by standard magnetic measurements shows that the surface magnetic behavior is different from the bulk one.