Magnetodielectric Effect in Crystals of the Noncentrosymmetric CaOFeS at Low Temperature

C. Delacotte (1, 2) , O. Perez (2) , A. Pautrat (2) , David Berthebaud (2) , S. Hébert (2) , E. Suard (3) , D. Pelloquin (2) , A. Maignan (2)

1 LaMIPS - Laboratoire de Microélectronique et de Physique des Semiconducteurs
2 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
3 ILL - Institut Laue-Langevin

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 Ca2+ 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. (Figure Presented). © 2015 American Chemical Society.

Mots clés: Phase transitions; Space group; Physical and chemical processes; Crystal structure; Insulators

Domaines: Chimie; Cristallographie; Matériaux; Chimie théorique et/ou physique

C. Delacotte, O. Perez, A. Pautrat, David Berthebaud, S. Hébert, et al.. Magnetodielectric Effect in Crystals of the Noncentrosymmetric CaOFeS at Low Temperature. Inorganic Chemistry, 2015, 54 (13), pp.6560-6565. ⟨10.1021/acs.inorgchem.5b00879⟩. ⟨hal-02184139⟩