| Abstract
| - New synthesized orthorhombic Sr4Fe2O6CO3 including two types of carbonate configurations (“coat hanger” and “flag”) presents a monoclinic distortion at 220 K, observed by electron microscopy, going with a spin canting and modifications of magnetic susceptibility, heat capacity, neutron diffraction, and Mössbauer results. EFG calculations allow one to understand the broadening of Mössbauer lines.
- The oxycarbonate Sr4Fe2O6CO3 has been revisited, using a new synthesis route. Itsmicrostructure has been established by electron microscopy and evidences an orthorhombic−monoclinic distortion at 220 K. The latter is associated with a spin reorientation (≈7°) visiblein magnetic susceptibility, heat capacity, and neutron diffraction studies. To understandthe structural transition, particular attention has been paid for the carbonate groups: theyadopt a specific orientation within a layer but different in successive layers, which involvedisorder along c⃗ and order in the (a,b) plane and are at the origin of the unusual broadeningof the Mössbauer lines.
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