Antiferromagnetic ordering in the novel Dy3Ge4 and DyGe1.3 compounds studied by neutron diffraction and magnetic measurements

[摘要] The magnetic ordering of the novel binary compounds Dy3Ge4 and DyGe13(1) has been studied by neutron diffraction and magnetic measurements. Dy,Ge, with the Er,Ge, structure type (space group Cmcm) displays a two step antiferromagnetic ordering below T-N=19 K. The two Dy sites (Dy-1:8(f) and Dy-2:4(c)) order independently with two distinct order parameters associated with the same wave vector q = (0, 1, 0). Both sublattices have a uniaxial antiferromagnetic moment arrangement but with mutually perpendicular orientations. Dy-1 orders below T-N with the moments along the a-axis, Dy-2 orders only below T-1=6 K along the c-axis. At 1.4 K the moment values of Dy, and Dy, are 7.31(8) mu(B) and 5.6(3) mu(B), respectively. Their arrangement leads to a symmetry reduction described by the monoclinic magnetic space group Cp11 2(1)'/m i'(Sh(11)(55)). The two-dimensional canted antiferromagnetic structure is the result of a strong magnetocrystalline anisotropy and the presence of various types of magnetic interactions. The phase of DyGe1.3(1) composition with the AIB(2) structure type (space group P6/mmm) was detected as an impurity in the studied sample. It orders antiferromagnetically below T-N=16 K with collinear moment arrangement associated with a 2c-cell enlargement (q=0,0,1/2) described by the magnetic space group P(2c)11 2'/m' (Sh(11)(56)). At 1.4 K mu(Dy) = 7.2(2) mu B and is confined to the (001) plane. (C) 1997 Elsevier Science S.A.

[发布日期] 1997-11-14

[效力级别]  Proceedings Paper

[关键词] rare-earth germanides;antiferromagnetism;magnetic structures;neutron diffraction