RE3Sb3Zn2O14 (RE = La, Pr, Nd, Sm, Eu, Gd) is a series of novel pyrochlore-related materials with 2D Kagome lattices formed by RE3+ and Sb5+. The rare earth is the only magnetic ion in the structure; this family is therefore an archetype for exploring magnetic frustration on a 2D Kagome lattice.

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The crystal structures and magnetic properties of three previously unreported A 2 B 2 F 7 pyrochlore materials, NaSrMn 2 F 7 , NaCaFe 2 F 7 , and NaSrFe 2 F 7 are presented. In these compounds, either S=2 Fe 2+ or S=5/2 Mn 2+ is on the B site, while nonmagnetic Na and Ca (Na and Sr) are disordered on the A site. The materials, which were grown as crystals via the floating zone method, display high effective magnetic moments and large Curie-Weiss thetas. Despite these characteristics, freezing of the magnetic spins, characterized by peaks in the susceptibility or specific heat, is not observed until low temperatures. The empirical frustration index, f=-θcw/T f , for the materials are 36 (NaSrMn 2 F 7 ), 27 (NaSrFe 2 F 7 ), and 19 (NaCaFe 2 F 7 ). AC susceptibility, DC susceptibility, and heat capacity measurements are used to characterize the observed spin glass behavior. The results suggest that the compounds are frustrated pyrochlore antiferromagnets with weak bond disorder. The magnetic phenomena that these fluoride pyrochlores exhibit, in addition to their availability as relatively large single crystals, make them promising candidates for the study of geometric magnetic frustration.

We report the magnetic properties of compounds in the KBaRE(BO 3 ) 2 family (RE= Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb), materials with a planar triangular lattice composed of rare earth ions. The samples were analyzed by x-ray diffraction and crystallize in the space group R3m. Physical property measurements indicate the compounds display predominantly antiferromagnetic interactions between spins without any signs of magnetic ordering above 1.8 K. The ideal 2D rare earth triangular layers in this structure type make it a potential model system for investigating magnetic frustration in rare-earth-based materials.

The crystal structures and magnetic properties of RE3Sb3Mg2O14 (RE = La, Pr, Sm, Eu, Tb, Ho) with a perfect kagome lattice are presented and compared to RE3Sb3Zn2O14. Rietveld structure refinements were performed using X‐ray diffraction data, indicating that the layered compounds are fully structurally ordered. The compounds crystallize in a rhombohedral supercell of the cubic pyrochlore structure, in the space group R‐3m. Magnetic susceptibility measurements show no signs of magnetic ordering above 2 K. The RE3Sb3Mg2O14 family is similar to that of RE3Sb3Zn2O14; however, the series reported here features a fully ordered distribution of cations in both the nonmagnetic antimony and magnetic rare earth kagome lattices. Unlike the offsite disorder that Zn2+ experiences in RE3Sb3Zn2O14, the magnesium sites in RE3Sb3Mg2O14 are completely ordered. Here we compare the magnetic properties in both series of kagome compounds to determine how significant Zn2+'s positional ordering is within this structure type. The compounds reported here appear to be relatively defect‐free and are therefore model systems for investigating magnetic frustration on an ideal 2D rare earth kagome lattice.