The University of Southampton
University of Southampton Institutional Repository

Assessing the ability of first-order reversal curve (FORC) diagrams to unravel complex magnetic signals

Muxworthy, A.R., King, J.G. and Heslop, D. (2005) Assessing the ability of first-order reversal curve (FORC) diagrams to unravel complex magnetic signals Journal of Geophysical Research, 110, (B1), B01105. (doi:10.1029/2004JB003195).

Record type: Article


First-order reversal curve (FORC) diagrams for mixtures of different magnetic phases and bimodal distributions have been measured to examine the efficiency of the FORC method at unraveling complex magnetic signals. The FORC distributions for various magnetic minerals, including magnetite, maghemite, hematite, and goethite, and their linear additivity are assessed. Mixtures containing only hard magnetic minerals like hematite or goethite, which have relatively small spontaneous magnetizations (MS) and large magnetocrystalline anisotropies, can be adequately described by a linear addition of the two end-members, because there are virtually no magnetostatic interactions between the phases. Mixtures dominated by softer minerals like magnetite and maghemite are more susceptible to interactions and exhibit nonlinear behavior. When a hard phase with low MS like hematite is mixed with a softer phase with high MS like magnetite, it can still be identified using the FORC technique, whereas it is impossible to do so using standard magnetic hysteresis measurements. When the weaker phase can be identified, then weak-strong mixes add linearly; however, beyond a certain critical concentration the mineral with high MS swamps the magnetic signal and linearity breaks down. It is suggested that the FORC method is highly suitable for identifying small traces of hard magnetic minerals like hematite and goethite in the presence of minerals with high MS such as magnetite.

Full text not available from this repository.

More information

Published date: 2005
Keywords: FORC diagram, magnetic hysteresis, unmixing, iron oxides, goethite


Local EPrints ID: 24064
ISSN: 0148-0227
PURE UUID: cd06b5f9-468e-4424-bb66-7e6e12980ba4

Catalogue record

Date deposited: 20 Mar 2006
Last modified: 17 Jul 2017 16:15

Export record



Author: A.R. Muxworthy
Author: J.G. King
Author: D. Heslop

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton:

ePrints Soton supports OAI 2.0 with a base URL of

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.