Observing thermomagnetic stability of nonideal magnetite particles: good paleomagnetic recorders?

Almeida, T. P. , Kasama, T., Muxworthy, A. R., Williams, W., Nagy, L. and Dunin-Borkowski, R. E. (2014) Observing thermomagnetic stability of nonideal magnetite particles: good paleomagnetic recorders? Geophysical Research Letters, 41(20), pp. 7041-7047. (doi:10.1002/2014GL061432)

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Abstract

The thermomagnetic behavior of remanence-induced magnetite (Fe3O4) particles in the pseudo-single-domain (PSD) size range (~0.1–10 µm), which dominate the magnetic signature of many rock lithologies, is investigated using off-axis electron holography. Construction of magnetic induction maps allowed for the visualization of the vortex domain state in an individual Fe3O4 grain (~200 nm in diameter) as a function of temperature. Acquisition of a series of electron holograms at 100°C intervals during in situ heating up to 700°C demonstrates the vortex state of the Fe3O4 grain, in this instance, remains thermally stable close to its unblocking temperature and exhibits a similar in-plane remanent state upon cooling; i.e., the particle is effectively behaving like a uniaxial single-domain particle to temperatures near TC. Such particles are thought to be robust magnetic recorders. It is suggested that evidence for PSD behavior should therefore not preclude paleomagnetic investigation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Almeida, Dr Trevor
Authors: Almeida, T. P., Kasama, T., Muxworthy, A. R., Williams, W., Nagy, L., and Dunin-Borkowski, R. E.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Geophysical Research Letters
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0094-8276
ISSN (Online):1944-8007
Copyright Holders:Copyright © 2014 American Geophysical Union
First Published:First published in Geophysical Research Letters 41(20):7041-7047
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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