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Magnetodielectric Effect in Crystals of the Noncentrosymmetric CaOFeS at Low Temperature
Charlène Delacotte1, Olivier Pérez1, Alain Pautrat1
1†Laboratoire CRISMAT ENSICAEN, UMR CNRS 6508, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04, France.
Abstract:
Single crystals of the stoichiometric iron calcium oxysulfide CaOFeS have been grown by a solid-state reaction. Structural analysis of CaOFeS at room temperature by combining single-crystal X-ray diffraction data and transmission electron microscopy leads to a stoichiometric hexagonal noncentrosymmetric P63mc layered structure isostructural to CaOZnS. It is built from alternating layers made of FeOS3 tetrahedra sharing sulfur apexes and stacked with Ca(2+) planes. All Fe-O bonds are parallel to the stacking axis; this breaks the centrosymmetry, leading to a polar structure. The dielectric measurements reveal the existence of a magnetodielectric effect near 33 K in good agreement with the Neel temperature, as evidenced near 35 K by specific heat measurements reported by a different group.
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