Crystal and electronic structures and magnetic properties of Eu₃Tt₂As₄ (Tt = Si, Ge)

Two new europium-containing Zintl phases, Eu₃Si₂As₄ and Eu₃Ge₂As₄, were discovered from metal flux reactions and their structures were identified by using single-crystal X-ray diffraction. Both compounds crystallize in the monoclinic space group P2₁/c and are isotypic to Sr₃Ge₂As₄. Magnetic property studies were performed and the results proved the long-range antiferromagnetic behavior for Eu₃Ge₂As₄ but with a positive Weiss constant, which suggested the coexistence of both ferromagnetic and antiferromagnetic order of Eu 4f electrons in the structure. Density functional calculations were incorporated to understand the related magnetic properties as well. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)