First order reversal curves and intrinsic parameter determination for magnetic materials; limitations of hysteron-based approaches in correlated systems

TL;DR

This paper critically examines the limitations of the FORC method in determining intrinsic magnetic properties in correlated systems, revealing its validity only under weak correlation conditions and proposing a more general approach.

Contribution

It demonstrates the constraints of the FORC technique in correlated magnetic systems and introduces a more comprehensive method for intrinsic parameter extraction.

Findings

FORC method is valid only for weakly correlated systems

Strong correlations lead to inaccuracies in FORC-based SFD extraction

A more general approach is proposed for correlated magnetic systems

Abstract

The generic problem of extracting information on intrinsic particle properties from the whole class of interacting magnetic fine particle systems is a long standing and difficult inverse problem. As an example, the Switching Field Distribution (SFD) is an important quantity in the characterization of magnetic systems, and its determination in many technological applications, such as recording media, is especially challenging. Techniques such as the first order reversal curve (FORC) methods, were developed to extract the SFD from macroscopic measurements. However, all methods rely on separating the contributions to the measurements of the intrinsic SFD and the extrinsic effects of magnetostatic and exchange interactions. We investigate the underlying physics of the FORC method by applying it to the output predictions of a kinetic Monte-Carlo model with known input parameters. We show that the FORC method is valid only in cases of weak spatial correlation of the magnetization and suggest a more general approach.