Experimental evaluation of a roughness model of surface anisotropy in amorphous magnetic ribbons

Anomalous evolution of torque curves with the applied magnetic field in amorphous ribbons due to surface roughness

“…The anisotropy constant would be 190 J m Ϫ3 , which is in good agreement with the results obtained in samples of Vitrovac 6150 without the anomalous behavior of the torque. 9 These results confirm that the origin of the decreasing of T u vs H in these kinds of samples in the as-received state is the surface roughness of those samples. The anomalous behavior of the torque is exhibited by those samples whose surface roughness in the longitudinal direction is greater than in the transversal direction.…”

“…The directional order gives rise to a magnetic anisotropy in the longitudinal direction of the ribbon. 1 Then the only possible source of an in-plane magnetic anisotropy in the transversal direction of the ribbon is the surface roughness.…”

“…The method used to obtain the circular samples has been described elsewhere. 9 All the samples have an initial thickness of 25 m and an average diameter of 10 mm, large enough to perform reliable torque measurements. Random mechanical polishing was performed with 0.1 m grain size alumina.…”

“…This technique also produces additional information about the different origins of the in-plane magnetic anisotropy. 1 In general, when torque curves of amorphous ribbons are measured, their amplitude increases as the strength of the applied magnetic field increases, until the torque reaches its saturation value. This torque per unit volume is the in-plane magnetic anisotropy constant ͑Fig.…”

Influence of the dipolar interactions in the magnetization reversal asymmetry of hard–soft magnetic ribbons

“…8 Certain samples were cut disk shaped 12 with diameters of 15 mm which allows comparison of the hysteresis loop measurements along different in-plane directions of the disk without the effect of different demagnetizing factors. The magnetic hysteresis loops were obtained by means of a computer controlled inductive measurement system.…”