A variable variance Preisach model (garnet film)

Abstract

Abstruct-The analysis of an artifEial medium has led to a new type of Preisach model where the variance of the interaction field is a function of the magnetization. The "ideal" particles of this medium have no reversible magnetization and only interact magnetostatically with their neighbors. In this model, the line separating the positively and the negatively magnetized regions of the Preisach plane is not a staircase.

Magnetostatic interaction fields in first-order-reversal-curve diagrams

“…4͑b͒ that the variance displays nonlinear behavior, and that it would be necessary to implement an iterative algorithm to determine the IFD variance on real samples. 8,18 For the distributions of nonidentical grains, the parallel IFDs were on average better described by Gaussian distributions than Cauchy distributions, even though p had a maximum of only 15% for d = 1. This is in contrast to the theory of Berkov; 7 however, this disagreement is probably due to the magnetic systems in a FORC measurement never being in a truly disordered state, and to a lesser extent the fixed symmetry in our model.…”

“…The former is accommodated in the moving Preisach models, and the change in the IFD variance is taken into account in the variable variance Preisach model. 8 For the highly interacting systems parallel h I and M / M S are nearly linearly correlated ͓Fig. 3͑a͔͒, and for such cases a moving Preisach model will sufficiently describe the system.…”

“…The asymmetry is much more pronounced than in studies of other magnetic measurement procedures. 8,10,11 In Fig. 5͑a͒ the mean arithmetic mean of the IFD for the entire FORC measurement versus d for both the parallel and perpendicular directions is shown.…”

“…The interaction field distribution ͑IFD͒ of such ordered magnetic systems is often asymmetric and the arithmetic variance of the IFD as a function of the magnetization. [8][9][10][11] …”

Variable variance Preisach model for multilayers with perpendicular magnetic anisotropy

“…In this paper, we propose an implementation of the variable variance Preisach model (VVPM) [33] that fully accounts for the different magnetization processes of a multilayer with PMA, and successfully compare it in a quantitative manner to experimental hysteresis loops of a [CoFeB/Pd] n multilayer. This model allows us to identify whether a multilayer structure has significant in-plane components of the magnetization, and gives insights into the physics governing the different magnetization reversal mechanisms.…”