Magnetic phase diagrams of the U(M, M′) 2X 2 systems (M, M′  Co, Ni, Cu; X  Si, Ge)

Abstract

Magnetic phase diagrams of the U(M, M′) 2X 2 systems (M, M′  Co, Ni, Cu; X  Si, Ge) are presented. Most materials crystalline in the body-centered tetragonal ThCr 2Si 2-type structure. Ordered magnetic moments along the tetragonal axis are found on the uranium atoms in ferromagnetic basal planes, stacked according to commensurate and incommensurate structures. Characteristic k-wave vectors are (0, 0, 1) [AF-I], (0, 0, 1 2 ) [efimagnetic], (0, 0, 1 2 ) [AF-IA], and (0, 0, 0) [ferromagnetic]. Some U(Co, Ni) 2Ge 2 materials, crystalizing in primitive tetragonal CaBe 2Ge 2-type structure, are nonmagnetic, down to ≈ 15 K.