AC SUSCEPTIBILITY AND DOMAIN-WALL DYNAMICS IN IRON-BASED AMORPHOUS RIBBONS

The ac susceptibilities and domain structures of iron-based amorphous ribbons have been studied in as-quenched, zero-field annealed, and fie ld annealed states. The eddy-current analysis indicates that the low-f ield susceptibility always has roughly equal contributions from domain -wall displacements and domain magnetization rotations. Anomalous fluc tuations of susceptibility have been found which are attributed to a r epeated spontaneous process of domain wan disaccommodation due to loca l directional ordering and small thermally activated reconstruction in domain structure.