Complex antiferromagnetic order in the Cd$_6R$ approximants to the i-$R$-Cd quasicrystals

The observation of antiferromagnetic order in the Cd$_6R$ ($R$ = rare earths) approximants [1-2] to the recently discovered related i-$R$-Cd quasicrystals [3] provides new and exciting opportunities to unravel the nature of magnetism in these materials. We present single-crystal studies employing x-ray and neutron scattering that revealed complex antiferromagnetism in the Cd$_6R$ approximants. Resolution-limited magnetic Bragg peaks have been observed at lattice points forbidden by the center-symmetry and at incommensurate positions demonstrating long-range antiferromagnetic correlations between the $R$ moments. The work at the Ames Laboratory was supported by US DOE, Office of Basic Energy Sciences, DMSE, contract DE-AC02-07CH11358. Work at the Tokyo University of Science was supported by KAKENHI (Grant No. 20045017). \\[4pt] [1] M. G. Kim et al., Phys. Rev. \textbf{B 85} (2012) 134442. \\[0pt] [2] A. Kreyssig et al., Phil. Mag. Lett. \textbf{93} (2013) 512. \\[0pt] [3] A. I. Goldman et al., Nature Mater. \textbf{12} (2013) 714.