Strongly correlated electron behavior in a new member of the A n +1 B n X 3 n +1 homologous series: Ce 7 Co 6 Ge 19

While f-electron intermetallics are well-known as hosts for complex valence behavior, magnetism, and unconventional superconductivity, it remains a persistent challenge to design specific phenomena. Some guidance is provided by studies of large families of materials, such as those based on the AlB2, AuCu3, and BaAl4 structural subunits, where systematic trends in their electronic behavior have been observed. This suggests that an effective approach in developing designer materials is to incorporate multimodal stacking arrangements of well-understood building blocks. Here, we report results for Ce7Co6Ge19, the n = 6 member of a new homologous series, A(n+1)B(n)X(3n+1), that consists of subunits previously identified as having potential for unconventional magnetic behavior. We show that Ce7Co6Ge19 exhibits complex magnetism with evidence for frustration and Kondo lattice behavior that is directly related to what is seen in other n value analogs. Here, the added structural units introduce additional magnetic degrees of freedom, demonstrating that it is possible to rationally design magnetic complexity, and possibly other phenomena in this family of intermetallics.