QUASI-PERIODIC ANTIFERROMAGNETIC ORDER IN I-R8MG42ZN50 (R = TB, DY) QUASI-CRYSTALS

The icosahedral R8Mg42Zn50 quasi-crystals (R = Tb, Dy) exhibit a two-c omponent antiferromagnetic order at low temperature: (i) a long-range quasi-periodic structure following the icosahedral symmetry and charac terized by the propagation vector Q = (1/4, 0, 0, 0, 0, 0) in six-dime nsional notation, (ii) a short-range order which manifests itself thro ugh broad peaks on the neutron diffraction patterns. From these result s, two distinct sites for rare-earth atoms seem to be present in these quasi-crystals. (C) 1998 Elsevier Science B.V. All rights reserved.