Synthesis, magnetism and electronic structure of YbNi_2-xFe_xAl₈ (x=0.91) isolated from Al flux

The combination of ytterbium, nickel, iron in liquid aluminum resulted in the formation of the new intermetallic compound YbNi_2-xFe_xAl₈ (x=0.91) which adopts the CaCo₂Al₈ structure type with a=14.458(3) Å, b=12.455(3) Å, c=3.9818(8) Å and space group Pbam. Its resistivity drops with decreasing temperature, saturating to a constant value at lower temperatures. Above 50 K, the inverse magnetic susceptibility data follows Curie-Weiss Law, with a calculated μ_eff=2.19 μ_B. Although the observed reduced moment in magnetic susceptibility measurement suggests that the Yb ions in this compound are of mixed-valent nature, ab initio electronic structure calculations within density functional theory using LDA+U approximation give an f¹³ configuration in the ground state.