Magnetic properties and electronic structure of R3T4X4 compounds (R = Pr, Nd; T = Cu, Ag; X = Ge, Sn)

Polycrystalline samples of R3T4X4 (R = Pr, Nd; T = Cu, Ag; X = Ge, Sn) intermetallics were investigated by means of magnetometric and XPS methods. All these compounds crystallize in the orthorhombic Gd3Cu4Ge4-type structure. They were found to be antiferromagnets, except Pr3Ag4Ge4 which is a collinear ferromagnet. Analysis of the XPS valence band data indicates strong overlaps of the Pr 4f states with the Cu 3d states and the Nd 4f states with the Ag 4d states. Analysis of the R 3d states on the basis of the Gunnarsson–Schönhammer model gave the information on the hybridization of the 4f orbital with the conduction band. The results showed that the Pr-based compounds are characterized by larger values of the hybridization energy than the Nd-based compounds.