Abstract
The synthesis and characterization of Ce4Fe3Ge10, n = 3, member of the homologous series Ln(n+1)M(n)X(3n+1) (Ln = lanthanides, M = transition metal, X = tetrel), is reported. The structure can be modeled with the Cmcm space group adopting the Eu2Ni2-x Sn-5 structure type, with lattice parameters of a = 4.3323 (15) & Aring;, b = 35.507 (9) & Aring;, and c = 4.3069 (12) & Aring;. Members of the series for n > 2 consist of stacking of ordered (CeNiSi2 type) and disordered (BaNiSn3/AuCu3 type) subunits with the latter acting as a "spacer" between CeNiSi2 subunits. Although neither CeFeGe3 nor CeFe0.63Ge2 order magnetically down to 2 K, Ce4Fe3Ge10 is an antiferromagnet below 3.6 K. To rationalize the emergent magnetism: (i) we established the Kondo- and RKKY-interaction dominant regions for the Ce analogues adopting the BaNiSn3 and CeNiSi2 by creating an electronic landscape for each and (ii) mapped the strained subunits, due to stacking, within the series. We established that the CeFeGe3 subunit within Ce4Fe3Ge10 contracts and is located within the Kondo-interaction dominant region, while the CeFeGe(2 )subunit expands and is in the RKKY-interaction dominant region.