Physical interpretation of the hysteresis parameters in the theory of hysteresis (abstract)

One of the most important remaining issues in the theory of hysteresis is a complete description of the physical meaning of the parameters that define the model equations.1 In common with the Stoner--Wohlfarth theory of rotational processes, the theory of hysteresis provides one of the few theories of hysteresis based on underlying physical mechanisms, rather than curve fitting models. In this paper, it is shown that the parameter a, which governs the orientation of the anhysteretic curve, is related to the density of domains and the absolute temperature a=kBT/μ0 left-angle m right-angle, where left-angle m right-angle is the magnet moment of the average domain in the material, measured in A m2. In fact, the magnetic material can be treated thermodynamically as an assembly of pseudodomains, each with identical magnetic moment left-angle m right-angle, and each interacting with all the other domains via the coupling coefficient α, leading to a mean coupling field of αM. The pinning coefficient k is simply a measure of the energy dissipation caused by movement of domain walls. The dissipation energy is proportional to the change in magnetization, dE=μ0kdM. Finally, the reversible component of magnetization is due principally to domain wall bending, and the bending coefficient c is related to the domain wall surface energy γ, the average domain magnetization left-angle m right-angle, and the spacing between pinning sites l, according to the equation c=(left-angle m right-angle pl4/4γ)·Fmax, where Fmax is the maximum force exerted on the domain wall by a typical pinning site