Magnetic structure of the ternary germanide Ce3Ni2Ge7

Abstract The ternary germanide Ce 3 Ni 2 Ge 7 has been studied by means of neutron powder diffraction and Ce L III X-ray absorption (XAS). This compound which orders antiferromagnetically below T N =7.2(2) K, crystallizes in the orthorhombic (Cmmm space group) La 3 Co 2 Sn 7 -type structure where Ce atoms occupying two inequivalent crystallographic sites: Ce1 at 2d site and Ce2 at 4i site. Below T N , the antiferromagnetic structure of Ce 3 Ni 2 Ge 7 is collinear but only the Ce2 atoms carry a magnetic moment (1.98(2) μ B at 1.4 K). The absence of ordered magnetic moment on Ce1 atoms can be correlated to the average valence v =3.03(1), determined by X-ray absorption spectroscopy, suggesting an intermediate valence state of cerium in the 2d site.