Magnetic structures of non-cerium analogues of heavy-fermion Ce2RhIn8: case of Nd2RhIn8, Dy2RhIn8 and Er2RhIn8

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 to grow 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 N\'eel 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 TN.