The
most favorable structures and the types of magnetic ordering predicted
from first-principles-based methods in a family of closely related
transition-metal-rich indides EuT5In (T = Cu, Ag, Au) are
gauged against relevant experiments. The EuT5In compounds
adopt a different structure for each different coinage metalEuCu5In (hR42; R3̅m, a = 5.0933(7), c =
30.557(6) Å), EuAg5In (oP28; Pnma, a = 9.121(2), b =
5.645(1), c = 11.437(3) Å), and EuAu5In (tI14; I4/mmm, a = 7.1740(3), c = 5.4425(3)
Å)and crystallize with the Sr5Al9, CeCu6, and YbMo2Al4 structure
types, respectively. EuCu5In and EuAg5In order
antiferromagnetically at T
N = 12 and 6
K, respectively, whereas EuAu5In is ferromagnetic below T
C = 13 K. EuCu5In exhibits complex
magnetism: after the initial drop at T
N, the magnetization rises again below 8 K, and a weak metamagnetic-like
transition occurs at 2 K in μ0H = 1.8 T. The electronic
heat capacity of EuCu5In, γ = ∼400 mJ/(mol
K2), points to strong electronic correlations. Spin-polarized
densities of states suggest that the magnetic interactions in the
three materials studied are supported via mixing 4f and 5d states of Eu. A chemical bonding analysis
based on the Crystal Orbital Hamilton populations reveals the tendency
to maximize overall bonding as a driving force to adopt a particular
type of crystal structure.
A rhombohedral modification of europium pentanickel indide, r-EuNi(5)In, crystallizes in the R ̅3m space group and adopts the UCu(5)In structure type. The structure is closely related to the hexagonal, h-EuNi(5)In, form (CeNi(5)Sn type). Both EuNi(5)In modifications are composed of CaCu(5) (EuNi(5))-, MgCu(2) (InNi(2))- and NiAs (EuNi)-type slabs in a 1:2:1 ratio. The atoms in the structure have high coordination numbers, viz. 20 and 18 for europium, 14 for indium, and 12 and 10 for nickel. The structure features a two-dimensional network of (2)(∞)[Ni(8)] tetrahedral clusters arranged in the ab plane.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.