Publication Date:
2011-11-16
Description:
Low-temperature magnetic evolution of troilite sample, extracted from the Cape York IIIA octahedrite meteorite, was investigated by employing macroscopic magnetic measurement, Mössbauer spectroscopy, scanning electron microscopy (SEM) and backscattered electrons (BSE) microscopy, X-ray diffraction (XRD), electron microprobe analysis (EMA), and atomic absorption spectrometry (AAS). The study identified a magnetic transition at ≈70 K manifested itself in a similar manner as previously reported for troilite from the Bruderheim L6 chondrite meteorite. The data show that this transition is unlikely driven by impurity such as chromite and seems to be rather an intrinsic property of troilite. In this study, we unambiguously exclude the relation of this transition to the structural rearrangement like the Morin transition in hematite. Similarly, in-field Mössbauer data do not support the change of the canting angle in the spin structure of FeS above and below the transition. Mössbauer, XRD, and magnetic data, newly measured also for troilite from the Bruderheim L6 chondrite, demonstrate that both studied troilite samples exhibit nearly the same magnetic and structural characteristics. Thus, the nature of the transition occurring at ≈70 K in both samples has identical characteristics and its detection can be used as a simple general marker for highly stoichiometric FeS systems.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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