ISSN:
1432-2021
Keywords:
Mineral magnetism
;
Mössbauer spectroscopy
;
Mineraliennamen: Nontronite
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
Abstract On heating the paramagnetic clay mineral nontronite for ≈ 30 h at 970 °C in air, a new ferrimagnetic phase forms which was studied by magnetic techniques, microprobe analysis, x-ray diffraction and Mössbauer spectroscopy. The new phase has a Curie temperature T c ≈ 240°C and high magnetic anisotropy at room temperature with a spontaneous magnetization 〉12 Am2/kg. Semiquantitative microprobe analyses show Fe to be the dominating consistuent. X-ray analysis points to a lattice which may be similar to that of ɛ-Fe2O3 but differs from it in detail. 57Fe Mössbauer spectra, taken between 78 K and 295 °C, can be deconvoluted into three sextet subpatterns in the ferrimagnetic region which are well resolved at room temperature and exhibit a rather small line width. Above T c, a doublet is visible which is typical for Fe3+ ions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00308215
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