We report the observation of antiferromagnetic (AFM) transitions in 1/1 and 2/1 quasicrystal approximants having slightly different electron-per-atom $\left(e/a\right)$ ratios, in the same Au-Ga-Eu system, at Néel temperatures of 7.0 and 8.5 K, respectively. This clearly demonstrates that an antiferromagnetic order survives when the degree of approximation to the quasicrystals is raised provided that the $e/a$ ratio is kept nearly the same. Since, unlike the 1/1 approximant, the 2/1 approximant has all the building blocks necessary for the construction of the quasicrystal, this finding can be a significant leap toward the long-sought realization of an AFM quasicrystal.

• Received 4 September 2019

DOI:https://doi.org/10.1103/PhysRevB.100.180409