A hybrid Jiles-Atherton / stoner-wohlfarth magnetic hysteresis model for inductive sensors and actuators

Abstract

The Jiles-Atherton (JA) theory of hysteresis is currently used in the majority of CAD tools. The JA model provides precise results in the case of polycrystalline, multi-domain magnetic structures, whose flux-reversal is dominated by pinning mechanisms. Thermal and dynamic response including eddy-current loss and magnetic resonance can also be incorporated. However, it does not account for the shape- and magnetoelastic-anisotropy fields that severely affect the hysteresis loop of single-domain, thin-film structures. In this case the Stoner-Wohlfarth (SW) theory can be applied. Although the SW model provides precise results, it is rarely employed because: (a) it does not account for dynamic response and pinning loss, and (b) its classical formulation is complicated. In this work we expand the use of the alpha parameter employed in the JA theory to model the exchange interaction, in order to account for anisotropy fields. Thus, a hybrid JA/SW model is developed, which incorporates both models into one single formulation. In this way thermal-agitation effects, minor-loops, domain-wall pinning-loss, eddy-current loss, magnetic resonance, shape-, and magnetoelastic-anisotropy can be altogether modeled.