Magnetic ordering in GdAuCd

A polycrystalline sample of GdAuCd was prepared by reaction of the elements in a sealed tantalum ampoule in an induction furnace. The structure was studied by X-ray powder and single-crystal diffraction: ZrNiAl type, P (6) over bar 2m, a = 770.1(2), c = 396.0(1) pm, wR2 = 0.0493 for 252 F-2 values and 14 variables. The structure contains two crystallographically different gold sites with tricapped trigonal prismatic coordination: [Au1Cd(3)Gd(6)] and [Au2Cd(6)Gd(3)]. Together the gold and cadmium atoms form a three-dimensional [AuCd] network in which the gadolinium atoms fill distorted hexagonal channels. The magnetic and electronic properties have been studied by means of AC and DC magnetic susceptibility measurements as well as Gd-155 Mossbauer spectroscopy on powder samples. It was found that GdAuCd orders antiferromagnetically at T-N = 66.5 K. (C) 2004 Elsevier B.V. All rights reserved.