Initial susceptibility vs. applied stress in amorphous alloys with positive and negative magnetostriction

The dependence of initial susceptibility X on applied tensile/compressive stress σ has been determined for Fe and Co based amorphous alloys characterized by positive and negative magnetostriction, respectively. The contributions to X originating from coherent spin rotation (X_r) and domain wall motion (X_w) are separated by means of suitably devised experiments and found to correlate with the evolution of the domain structure vs. σ, as directly verified by means of magnetooptical Kerr effect observations. High tensile stresses produce entirely longitudinal (transverse) domain structure in Fe (Co) based ribbons. The longitudinal (transverse) pattern evolves into a transversal (longitudinal) one by progressively changing tension into compression. X_r and X_w correspondingly pass through a maximum at intermediate stress values