Description of magnetic interactions and Henkel plots by the Preisach hysteresis model

The ability of the scalar Preisach model (PM) to describe magnetic interactions and Henkel plots is discussed. It is shown that the random interactions described by the PM switching field distribution p(α,β) always have a net demagnetizing-like effect on remanences. The connection between the properties of p(α,β) and those of Henkel plots is investigated. In particular, it is shown that, when p(α,β)=f(α)f(-β), the remanence law i _d/i_∞=1-2√i_r/i_∞ , completely independent of f(α), holds. The joint presence of random interactions and mean-field effects is dealt with through the moving PM (MPM), in which an additional field proportional to magnetization acts on each PM elementary loop. The classification of Henkel plots by MPM is discussed. In particular, it is shown that Henkel plots exhibiting both magnetizing-like and demagnetizing-like deviations are a certain indication of the joint presence of random interactions and magnetizing-like mean-field effects. Theoretical predictions are compared with recent Henkel plot measurements on magnetic recording media, superconductors, thin films, hard magnets, and soft magnetic materials