HYSTERESIS MODELING AND MICROSTRUCTURAL ANALYSIS OF SOFT AMORPHOUS-ALLOYS

the dynamic Preisach model is applied to the study of Fe-based and Go- based amorphous alloys. characterized by different microstructural con ditions. It is shown that all static and dynamic hysteresis properties are correctly predicted by the dynamic Preisach model by associating with each material a structural parameter, lambda, which represents th e linear dimension of the correlation regions providing coherent magne tization changes. The dependence of this correlation length on anneali ng treatments is compared with Kerr-effect domain observations and str uctural data obtained by differential scanning calorimetry. It is foun d that lambda has a role comparable to that of grain size in micro-cry stalline alloys. In particular, it is shown that the linear relation h olds, H-c = H-c0 + c/lambda, between the static coercive field H-c and 1/lambda, where the slope c depends on the magnetostriction constant of the material and the amount of quenched-in stresses, whits the offs et H-c0 is connected to surface characteristics.