REVERSIBLE MAGNETIZATION PROCESSES IN AMORPHOUS-ALLOYS

The role of coherent moment rotations on the magnetization process of soft amorphous alloys has been investigated in theory and experiment. In particular, a theoretical formulation for the reversible magnetization curve has been worked out by modeling the spatial distribution of the magnetization in ribbon-shaped samples and its evolution under an applied field. Such a distribution is assumed to derive from the combined effects of frozen-in random anisotropies and the macroscopic in-plane anisotropy. Experiments arc reported concerning Fe-based alloy ribbons, where a range of macroscopic anisotropy values are achieved through the application of a variable tensile/compressive stress. In order to determine the reversible component of the magnetization curve I(rev)(H) a method is devised that exploits the susceptibility after-effect, which permits one to discriminate between contributions from coherent spin rotations and domain wall displacements. The so obtained I(rev)(H) curve and its dependence on stress are found to agree with the theoretical prediction.