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Magnetic interaction in ferrous antimonite, FeSb2O4, and some derivatives
R D Bayliss1, F J Berry, B P de Laune
1School of Chemistry, The University of Birmingham, Birmingham B15 2TT, UK.
Summary
Mössbauer spectroscopy reveals that lead doping in ferrous antimonite (FeSb(2)O(4)) causes iron oxidation. The material exhibits a unique magnetic structure with coexisting magnetic and non-magnetic iron states.
Area of Science:
- Solid State Chemistry
- Materials Science
- Inorganic Chemistry
Background:
- Ferrous antimonite (FeSb(2)O(4)) is structurally similar to lead pyroantimonate (Pb(3)O(4)).
- Doping with aliovalent cations can significantly alter material properties.
- Understanding oxidation states and magnetic behavior is crucial for materials development.
Purpose of the Study:
- To investigate the structural and magnetic properties of FeSb(2)O(4) and its lead- and cobalt-doped variants.
- To determine the oxidation states of antimony and iron within the doped materials.
- To explore the influence of doping on the magnetic ordering and electronic transitions.
Main Methods:
- Utilized (57)Fe and (121)Sb Mössbauer spectroscopy for detailed elemental and oxidation state analysis.
- Synthesized undoped ferrous antimonite and doped variants with compositions FeSb(1.5)Pb(0.5)O(4) and Co(0.5)Fe(0.5)Sb(1.5)Pb(0.5)O(4).
- Analyzed spectral data to identify oxidation states and magnetic interactions.
Main Results:
- Confirmed antimony exists as Sb(3+) in all studied compounds.
- Observed partial oxidation of Fe(2+) to Fe(3+) upon introduction of Pb(2+) at the antimony site.
- Identified a quasi-one-dimensional magnetic structure where Fe(2+) ions in a non-magnetic state coexist with magnetically ordered Fe(3+) ions.
Conclusions:
- Lead doping induces significant changes in the oxidation state of iron in ferrous antimonite.
- The material does not exhibit a Verwey-type transition involving electron delocalization.
- The observed magnetic structure is characterized by the coexistence of different magnetic states for iron ions.
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