ChemInform Abstract: Synthesis, Structure and Properties of the Oxychalcogenide Series A₄O₄TiSe₄ (A: Sm, Gd, Tb, Dy, Ho, Er and Y).

Abstract

Polycrystalline samples of Ln4O4TiSe4 (Ln: Sm, Gd, Tb, Dy, Ho, Er and Y) are prepared by solid state reactions of Ln2O3, TiSe2, and Se (alumina crucible, 900°C, 72 h). The compounds crystallize in the monoclinic space group C2/m (powder XRD). The structures contain infinite ribbons of edge-sharing Ln 4 O and Ln 3 TiO tetrahedra, which are linked by chains of edge-sharing TiSe 4 O 2 octahedra. The materials are semiconductors with electronic band gaps between 0.378 and 0.254 eV. Gd4O4TiSe4 shows a significant increase in susceptibility between 2.5 and 4 K probably due to spin canting prior to the onset of full antiferromagnetic order. Dy4O4TiSe4 and Ho4O4TiSe4 order antiferromagnetically below 4 K. -(TUXWORTH, A. J.; EVANS*, J. S. O.; J. Solid State Chem. 210 (2014) 1, 188-194, http://dx.