The Solid Solution Eu_1–xSr_xAuIn

Abstract

EuAuIn and SrAuIn (TiNiSi type structure, space group Pnma ) form a complete solid solution Eu 1– x Sr x AuIn. Samples with x = 0.2, 0.4, 0.5, 0.6 and 0.8 were prepared by melting of the elements in sealed tantalum ampoules followed by slow cooling. The samples were characterized through Guinier powder patterns. The X‐ray data confirm Vegard type behavior. The crystal structures of Eu 0.8 Sr 0.2 AuIn and Eu 0.5 Sr 0.5 Au 1.02 In 0.98 were refined from single‐crystal X‐ray diffraction data in order to confirm the Eu/Sr site occupancies. Temperature‐dependent magnetic susceptibility data confirm divalent europium. The Néel temperature linearly drops from 21.0 K for EuAuIn and long‐range magnetic ordering is still present in the x = 0.8 sample with T N = 4.1 K. Low‐field measurements indicate two successive magnetic ordering temperatures for all samples, resulting from a complex interplay of antiferromagnetic and ferromagnetic interactions, similar to the tetrelides EuMg X ( X = Si, Ge, Sn). 151 Eu Mössbauer spectra confirm the divalent ground state and show complex magnetic hyperfine field splitting at 6 K.