Structure refinement, magnetic susceptibility, electrical conductivity and europium-151 Mössbauer spectroscopy of EuNiIn4

Abstract

The title compound was prepared by a reaction of the elemental components at 970 K in a tantalum tube. EuNiIn₄ adopts the orthorhombic YNiAl₄-type structure. It was refined from single-crystal X-ray data: space group Cmcm, a= 447.31 (4) pm, 6= 1695.88(15) pm, c= 722.32(6) pm, V= 0.5479(1) nm³, Z = 4, wR2 = 0.046l, 637 F² values and 24 variable parameters. Magnetic susceptibility measurements show Curie–Weiss behaviour above 50 K. At 16(1) K, a phase transition to the antiferromagnetic state is observed in the temperature dependence of the inverse magnetic susceptibility. The experimental magnetic moment µ_exp= 7.86(5)µ_B/Eu is close to that of the free Eu⁺² ion µ_eff=7.947 µ_B. EuNiIn₄ is a good metallic conductor with a specific resistivity of 14 µΩcm at room temperature. ¹⁵¹Eu Mössbauer measurements can be fit by a single Eu site with an isomer shift δ=– 10.9 mm s^–1 against EuF₃ which is typical for divalent Eu. At T_N, = 32(1) K magnetic order begins, which can be detected by Móssbauer spectroscopy when the fluctuation rate is smaller than the inverse half-life of the excited state of the ¹⁵¹Eu nuclide, which occurs in parts of the present sample only at temperatures significantly lower than T_N.