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

Three gadolinium scandium chalcogenides have been synthesized using Sb(2)Q(3) (Q = S, Se) fluxes at 975 degrees 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 anti ferromagnetic ordering below 3 K with a weak ferromagnetism. Gd1.05Sc0.95Se3 undergoes a ferromagnetic transition around 5K. The optical band gaps for Gd3.04Sc0.96S6, GdScS3, and Gd1.05Sc0.95Se3 are 1.5, 2.1, and 1.2 eV, respectively. (C) 2009 Elsevier Inc. All rights reserved.