Synthesis, structure and properties of the oxychalcogenide series A4O4TiSe4 (A=Sm, Gd, Tb, Dy, Ho, Er and Y)

Tuxworth, A.J.; Evans, J.S.O.

Abstract

Seven oxyselenide materials have been synthesised with composition A4O4TiSe4 (A=Sm, Gd–Er, Y) via solid state reactions of A2O3, TiSe2 and Se at 900 °C. They are all isostructural with Gd4O4TiSe4. Structures have been refined from powder X-ray diffraction data and have monoclinic C2/m symmetry with unit cell parameters of a≈15.7 Å, b≈3.75 Å, c≈9.65 Å and β≈117.5°. They contain infinite ribbons of edge-sharing A4O and A3TiO tetrahedra 4 units wide, which are linked by chains of TiSe4O2 edge-sharing octahedra. Compositions A=Gd–Ho, Y are semiconductors with conductivities 1–3 Sm−1 at 300 K, with electronic band gaps of between 0.25 and 0.37 eV. Magnetic susceptibility is reported from 1.8 K to 300 K for compositions A=Gd–Ho. Rare earth moments appear to order antiferromagnetically at low temperatures with Gd and Tb showing evidence of ferromagnetism due to spin canting over a narrow temperature range close to TN.

Citation

Tuxworth, A., & Evans, J. (2014). Synthesis, structure and properties of the oxychalcogenide series A4O4TiSe4 (A=Sm, Gd, Tb, Dy, Ho, Er and Y). Journal of Solid State Chemistry, 210(1), 188-194. https://doi.org/10.1016/j.jssc.2013.11.006

• Journal Article Type: Article
• Acceptance Date: Nov 2, 2013
• Online Publication Date: Nov 21, 2013
• Publication Date: Feb 1, 2014
• Deposit Date: May 4, 2015
• Publicly Available Date: Feb 13, 2018
• Journal: Journal of Solid State Chemistry
• Print ISSN: 0022-4596
• Electronic ISSN: 1095-726X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 210
• Issue: 1
• Pages: 188-194
• DOI: https://doi.org/10.1016/j.jssc.2013.11.006