R2RhIn8 compounds (space group P4/mmm, R is a rare-earth element) belong to a large group of structurally related tetragonal materials which involves several heavy-fermion superconductors based on Ce. We have succeeded in growing single crystals of compounds with Nd, Dy, and Er, and following our previous bulk measurements, we performed neutron-diffraction studies to determine their magnetic structures.
The Laue diffraction experiment showed that the antiferromagnetic order below the Nccl temperature is in all three compounds characterized by the propagation vector k = (1/2,1/2,1/2). The amplitude and direction of the magnetic moments, as well as the invariance symmetry of the magnetic structure, were determined by subsequent experiments using two-and four-circle diffractometers.
The critical exponents were determined from the temperature dependence of the intensities below T-N