Low-temperature magnetic properties of greigite (Fe3S4)


Chang, Liao, Roberts, Andrew P., Rowan, Christopher J., Tang, Yan, Pruner, Petr, Chen, Qianwang and Horng, Chorng-Shern (2009) Low-temperature magnetic properties of greigite (Fe3S4). Geochemistry Geophysics Geosystems, 10, (1), Q01Y04. (doi:10.1029/2008GC002276).

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Description/Abstract

We provide comprehensive low-temperature magnetic results for greigite (Fe3S4) across the spectrum from superparamagnetic (SP) to multi-domain (MD) behavior. It is well known that greigite has no low-temperature magnetic transitions, but we also document that it has strong domain-state dependence of magnetic properties at low temperatures. Blocking of SP grains and increasing thermal stability with decreasing temperature is apparent in many magnetic measurements. Thermally stable single-domain greigite undergoes little change in magnetic properties below room temperature. For pseudo-single-domain (PSD)/MD greigite, hysteresis properties and first-order reversal curve diagrams exhibit minor changes at low temperatures, while remanence continuously demagnetizes because of progressive domain wall unpinning. The low-temperature demagnetization is grain size dependent for PSD/MD greigite, with coarser grains undergoing larger remanence loss. AC susceptibility measurements indicate consistent blocking temperatures (TB) for all synthetic and natural greigite samples, which are probably associated with surficial oxidation. Low-temperature magnetic analysis provides much more information about magnetic mineralogy and domain state than room-temperature measurements and enables discrimination of individual components within mixed magnetic mineral assemblages. Low-temperature rock magnetometry is therefore a useful tool for studying magnetic mineralogy and granulometry of greigite-bearing sediments.

Item Type: Article
ISSNs: 1525-2027 (print)
Related URLs:
Keywords: greigite, magnetic properties
Subjects: Q Science > QE Geology
Q Science > QC Physics
Divisions: University Structure - Pre August 2011 > School of Ocean & Earth Science (SOC/SOES)
ePrint ID: 68610
Date Deposited: 03 Sep 2009
Last Modified: 27 Mar 2014 18:48
URI: http://eprints.soton.ac.uk/id/eprint/68610

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