MAGNETIC PHASE-DIAGRAMS OF THE U(M,M')(2)X(2) SYSTEMS (M,M'=CO, NI, CU X=SI, GE)

Magnetic phase diagrams of the U(M, M')(2)X(2) systems (M, M' = Co, Ni , Cu; X = Si, Ge) are presented. Most materials crystallize in the bod y-centered tetragonal ThCr2Si2-type structure. Ordered magnetic moment s along the tetragonal axis are found on the uranium atoms in ferromag netic basal planes, stacked according to commensurate and incommensura te structures. Characteristic k-wave vectors are (0,0,1) [AF-1], (0,0, 2/3) [ferrimagnetic], (0,0,1/2) [AF-IA], and (0,0,0) [ferromagnetic]. Some U(Co,Ni)(2)Ge-2 materials, crystallizing in primitive tetragonal CaBe2Ge2-type structure, are nonmagnetic, down to approximate to 15 K.