title: Indium flux-growth of Eu2AuGe3: a new germanide with an AlB2 superstructure.
abstract: The germanide Eu(2)AuGe(3) was obtained as large single crystals in high yield from a reaction of the elements in liquid indium. At room temperature Eu(2)AuGe(3) crystallizes with the Ca(2)AgSi(3) type, space group Fmmm, an ordered variant of the AlB(2) type: a = 857.7(4), b = 1485.5(10), c = 900.2(4) pm. The gold and germanium atoms build up slightly distorted graphite-like layers which consist of Ge(6) and Au(2)Ge(4) hexagons, leading to two different hexagonal-prismatic coordination environments for the europium atoms. Magnetic susceptibility data showed Curie-Weiss law behavior above 50 K and antiferromagnetic ordering at 11 K. The experimentally measured magnetic moment indicates divalent europium. The compound exhibits a distinct magnetic anisotropy based on single crystal measurements and at 5 K it shows a metamagnetic transition at ∼10 kOe. Electrical conductivity measurements show metallic behavior. The structural transition at 130 K observed in the single crystal data was very well supported by the conductivity measurements. (151)Eu Mössbauer spectroscopic data show an isomer shift of -11.24 mm/s at 77 K, supporting the divalent character of europium. In the magnetically ordered regime one observes superposition of two signals with hyperfine fields of 26.0 (89%) and 3.5 (11%) T, respectively, indicating differently ordered domains.
authors.affiliation: Department of Chemistry, Northwestern University, 2145 N. Sheridan Road, Evanston, Illinois 60208-3113, USA.
authors.forename: C Peter
authors.initials: CP
authors.lastname: Sebastian
authors.forename: Christos D
authors.initials: CD
authors.lastname: Malliakas
authors.forename: Maria
authors.initials: M
authors.lastname: Chondroudi
authors.forename: Inga
authors.initials: I
authors.lastname: Schellenberg
authors.forename: Sudhindra
authors.initials: S
authors.lastname: Rayaprol
authors.forename: Rolf-Dieter
authors.initials: RD
authors.lastname: Hoffmann
authors.forename: Rainer
authors.initials: R
authors.lastname: Pöttgen
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis