Syntheses, structures, magnetism, and optical properties of gadolinium scandium chalcogenides

Three gadolinium scandium chalcogenides have been synthesized using Sb2Q3 (Q=S, Se) fluxes at 975 °C. Gd3.04Sc0.96S6, GdScS3, and Gd1.05Sc0.95Se3 are crystallized in U3ScS6 type, GdFeO3 type, and UFeS3 type structures, respectively. The magnetic susceptibilities for these compounds follow the Curie–Weiss law above their transition temperatures. The effective magnetic moments are close to calculated values for free Gd3+ ions. The Weiss constants for Gd3.04Sc0.96S6, GdScS3, and Gd1.05Sc0.95Se3 are determined to be −3.3(1), −4.5(4), and 1.5(1) K, respectively. Gd3.04Sc0.96S6 orders antiferromagnetically below 9 K. GdScS3 exhibits an antiferromagnetic ordering below 3 K with a weak ferromagnetism. Gd1.05Sc0.95Se3 undergoes a ferromagnetic transition around 5 K. The optical band gaps for Gd3.04Sc0.96S6, GdScS3, and Gd1.05Sc0.95Se3 are 1.5, 2.1, and 1.2 eV, respectively.