Ferromagnetic or antiferromagnetic Fe III spin configurations in sheet silicates
| ISSN: |
1432-2021
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| Source: |
Springer Online Journal Archives 1860-2000
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| Topics: |
Chemistry and Pharmacology
Geosciences
Physics
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| Notes: |
Abstract Mössbauer spectra of glauconite and nontronite recorded at temperatures down to 1.3K and in applied fields up to 4.5 T show that Fe III spin configurations are respectively ferromagnetic and antiferromagnetic. It is shown that in a particular material depending on the distribution and concentration of Fe III in the silicate sheet either mode might occur. A new model of competing nearest-neighbour (J 1) and next-nearest-neighbour (J 2) magnetic exchange interactions in the triangular lattice is introduced to account for the results. From available magnetic susceptibilities we estimate ∣J 1∣∼6∣J 2∣. The results lead to the conclusion that the Fe III cations are highly ordered in glauconite and occupy cis sites so as to maximize their mutual separations.
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| Type of Medium: |
Electronic Resource
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| URL: |