Growth, discovery and characterization of single crystalline Eu${}_{0.8}$Pt${}_6$Al${}_{16.4}$

We report the discovery of a ternary compound, Eu${}_{0.8}$Pt${}_6$Al${}_{16.4}$. We determine its chemical and structural characteristics based on energy-dispersive X-ray spectroscopy as well as both powder and single-crystal X-ray diffraction, demonstrating that it crystallizes in a hexagonal structure type EuPt${}_6$Al${}_{17}$ with no reported structural analog. The electronic and magnetic properties are characterized by temperature- and field-dependent magnetization, and temperature-dependent resistance measurements, revealing that the Eu${}^{2+}$ magnetic moments order antiferromagnetically below 2.8 K.