The Influence of the magnetic history on the loop shift behavior of Fe-based amorphous ribbons

The asymmetrical hysteresis loops were observed for the annealed Fe ₆₅Co₁₅Si₅b₁₅amorphous ribbons. The curves, which shift from the zero point of H axis with a unilateral step magnetization, exhibit the special magneticfeatures of the ribbons. A few magnetic crystalline phases were identified in the amorphous matrix of annealed ribbons by microstnicture measurement. It was also found that the Z-oriented local magnetic domains emerge in the surface of ribbons with the loops shift behavior. Subsequent magnetic torque measurement indicated that the unidirectional magneti anisotropy was induced in the amorphous ribbons with proper thermomagnetic annealing. These obtained evidences support our understanding that the magnetic history caused by thermomagnetic treatment plays a main role in promoting the formation of the asymmetrical loops.