Journal Article

FZJ-2015-02609

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Magnetic characterization of synthetic titanomagnetites: Quantifying the recording fidelity of ideal synthetic analogs

Almeida, T. P. (Corresponding Author) ; Muxworthy, A. R. ; Williams, W. ; Kasama, T. ; Dunin-Borkowski, R.FZJ*

2014
Wiley Hoboken, NJ

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Please use a persistent id in citations: doi:10.1002/2013GC005047

Abstract: A series of four synthetic basalts comprising titanomagnetite (Fe3-xTixO4) grains of varied size and titanium content have been produced by a glass-ceramic method. Complementary characterization techniques of X-ray diffractometry, secondary electron microscopy, and transmission electron microscopy (TEM) demonstrate the reaction product composition consisted of mainly Fe3-xTixO4, pyroxene hedenbergite, fayalite, and SiO2. The samples exhibit bimodal distributions of larger (<2 µm) and smaller Fe3-xTixO4 particles (<50 nm in diameter), the latter found inside pyroxene crystals, as well as the sporadic occurance of dendritic Fe3-xTixO4 structures. Magnetic measurements show their bulk characteristics fall into two groups: Ti-rich titanomagnetite samples with varying Ti content; and near-stoichiometric magnetite. The TEM technique of off-axis electron holography allowed for visualization of the magnetic behavior of the synthetic Fe3-xTixO4 grains. Energy dispersive X-ray analysis and off-axis electron holography confirmed the small Fe3-xTixO4 grains (<50 nm) confined within glassy pyroxene regions to be Fe-rich and single domain, carrying strong magnetic signals, compared to the relatively magnetically weak larger Fe3-xTixO4 grains (x ∼ 0.6). The large grains in the pure magnetite sample are shown to be pseudo-single domain in nature. The quenching process involved in synthesis is considered similar to that of pillow basalts found at mid-ocean ridges and hence the reaction products are thought ideal in terms of characterization and understanding, for the purpose of studying natural systems.

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Contributing Institute(s):

1. Mikrostrukturforschung (PGI-5)

Research Program(s):

1. 42G - Peter Grünberg-Centre (PG-C) (POF2-42G41) (POF2-42G41)

Appears in the scientific report 2014

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Database coverage:
Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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