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 P2(1)/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.