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(/spl alpha/,/spl beta/) always have a net demagnetizing-like effect on remanences. The connection between the properties of p(/spl alpha/,/spl beta/) and those of Henkel plots is investigated. In particular, it is shown that, when p(/spl alpha/,/spl beta/)=f(/spl alpha/)f(/spl minus//spl beta/), the remanence law i/sub d//i/sub /spl infin//=1/spl minus/2/spl radic/i/sub r//i/sub /spl infin//, completely independent of f(/spl alpha/), 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.<
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