Magnetic, electronic and transport properties of the Ce3Ag4X4 (X=Ge, Sn) compounds

Abstract The work presents results of magnetometric, transport, XPS and neutron diffraction measurements performed on polycrystalline samples of Ce 3 Ag 4 X 4 (X=Ge, Sn). The X-ray and neutron diffraction data indicate that these compounds crystallize in an orthorhombic structure of the Gd 3 Cu 4 Ge 4 -type. The magnetometric data reveal a ferromagnetic-like behaviour below 10 K in the case of Ce 3 Ag 4 Ge 4 and a weak antiferromagnetic-like maximum at 9 K for Ce 3 Ag 4 Sn 4 . The neutron diffraction data do not evidence magnetic ordering in any of the two compounds. Temperature variations of the electrical resistivity and thermoelectric power suggest their metallic character. The Ce 3d X-ray photoemission spectra show that both compounds are mixed valence systems. Analysis of the f 2 peak weight using the Gunnarsson–Schonhammer theory suggests a hybridization constant of 169 meV for Ce 3 Ag 4 Ge 4 and 82 meV for Ce 3 Ag 4 Sn 4 . The valence band spectra are dominated by the Ag 4d states contributions. Broad and very weak peaks extending between 0 and 4 eV correspond to the Ce 5d6s 2 states.