An investigation of structural parameters and magnetic and optical properties of EuLn2Q4 (Ln=Tb–Lu, Q=S, Se)

EuLn2Q4 (Ln=Tb–Lu; Q=S, Se) has been synthesized using Sb2Q3 (Q=S, Se) fluxes at 1000 °C. These compounds crystallize in a CaFe2O4-type three-dimensional channel structure that is built from edge-shared double rutile chains of [LnQ6] octahedra running down the b-axis. Each double chain is connected at the vertices to four other double chains to form open channels where bicapped trigonal prismatic Eu2+ ions reside. All of these compounds show antiferromagnetic ordering with Neel temperatures, TN∼3–4 K. The optical band gaps for EuTb2Se4, EuDy2Se4, EuHo2Se4, EuEr2Se4, EuTm2Se4, EuYb2Se4 EuLu2Se4, and EuYb2S4 are found to be 2.0, 1.8, 1.8, 1.7, 1.8, 1.3, 1.7, and 1.6 eV, respectively.