Characterization of ferromagnetics as working in the parametrically excited circuits

A method of characterization of the parametrical behavior of ferromagnetics is proposed, based on the concept of instantaneous parameters. Instantaneous permeability and instantaneous resistivity introduced as small signal parameters are discussed from both physical and engineering points of view. The role of domain walls motion model is emphasized, because of the predominance of this model within the frequency range of common practical interest. The measuring technique is described and some experimental results are quoted, pertinent to low-coercivity square-loop ferrite material of Mn-Mg type. The characteristics of the instantaneous parameters, plotted as the functions of magnetization state, can be easily recalculated into time functions. Thus, the new parameters advanced can be utilized directly in the analysis of the networks with time-varying parameters. This work refers to the formal treatments of parametric circuits, such as the generalized theory of the frequency-converting networks developed by Duinker [17]. It is believed, that the characteristic parameters advanced are of better adequacy and lead to more accurate results than are obtainable by the use of analytical B-H curve approximations, which sometimes completely fail the real physical and electrical properties of the magnetic circuits under parametric excitation.