Frequency dependence of hysteresis curves in conducting magnetic materials (abstract)

An extension of the differential equation for hysteresis has been developed, which takes into account the effects of eddy currents on the hysteresis curves in electrically conducting media. In the derivation presented, it is assumed that the frequency of the applied field is low enough (or the thickness of the material medium small enough) that the skin effect can be ignored. In this case, the DC hysteresis equation is extended by the addition of a term depending on (i) the rate of change of magnetization with time, (ii) the resistivity of the material, and (iii) the shape of the specimen. In the limit, as the frequency of the exciting field tends to zero, the frequency-dependent hysteresis curve approaches the DC curve