EuZn2Si2 and EuZn2Ge2 grown from Zn or Ga(In)/Zn flux

Single crystals of the novel ternary compounds EuZn2Si2 and EuZn2Ge2 were grown from pure gallium, indium, or zinc metal used as a flux solvent. Crystal properties were characterized using X-ray single-crystal analyses via Gaudolfi and Weissenberg film techniques and by four-circle X-ray single-crystal diffractometry. The new compounds crystallize with ternary derivative structures of BaAl4 i.e., EuZn2Si2 with ThCr2Si2-type (a = 0.42607(2) nm, c = 1.03956(5) nm, I4/mmm, R-1 = 0.038 and EuZn2Ge2 with CaBe2Ge2-type (a = 0.43095(2) nm, c = 1.07926(6) nm, P4/nmm, R-1 = 0.067). XAS and magnetic measurements on EuZn2Si2 and EuZn2Ge2 revealed in both compounds the presence of Eu2+ ions carrying large magnetic moments, which order magnetically at low temperatures. The magnetic phase transition occurs at T-N = 16 and 7.5 K for the silicide and the germanide, respectively. In EuZn2Si2 there occurs a spin reorientation at 13 K and furthermore some canting of antiferromagnetically ordered moments below about 10K. In EuZn2Ge2 a canted anti ferromagnetic structure is formed just at T-N. (C) 2002 Elsevier Science.