M. Kuznietz et al., NEUTRON-DIFFRACTION AND AC SUSCEPTIBILITY STUDIES OF THE SOLID-SOLUTIONS UMM'X(2) (M, M'=CO, NI, CU, X=SI, GE), Journal of magnetism and magnetic materials, 137(3), 1994, pp. 322-328
Polycrystalline samples of the intermediate solid solutions of the UM(
2)X(2) compounds (M=Co, Ni, Cu; X=Si, Ge), namely UMM'X(2), have been
prepared and studied by ac susceptibility and neutron diffraction meas
urements. They crystallize in the body-centered tetragonal ThCr2Si2-ty
pe structure (space group I4/mmm) and order magnetically, with the exc
eption of UCoNiGe2, which crystallizes in the primitive tetragonal CaB
e2Ge2-type structure (space group P4/nmm) and does not order magnetica
lly. UCoNiSi2, UNiCuSi2, and UNiCuGe2 order antiferromagnetically belo
w T-N=(115 +/- 5), (150 +/- 2) and (140 +/- 5) K, respectively, with t
he AF-I structure of alternate (+-+-) ferromagnetic uranium basal plan
es and a wavevector k=(0, 0, 1). UCoCuSi2 and UCoCuGe2 order ferromagn
etically below T-C=(107 +/- 5) and (114 + 5) K and undergo transition
to the AF-I structure below T-o=(95 +/- 5) and (94 +/- 5) K, respectiv
ely. The uranium ordered moments are along the tetragonal axis. The ma
gnetic properties of the UMM'X(2) solid solutions are discussed and co
mpared with those of the UM(2)X(2) compounds.