Magnetic structures of Tb2Co3Si5 and Dy2Co3Si5 compounds

Neutron diffraction studies indicate that polycrystalline R2Co3Si5 (R = Tb and Dy) intermetallic compounds with monoclinic Lu2Co3Si5-type crystal stru cture have different magnetic structures. Tb2Co3Si5 has a sine wave modulat ed structure described by the wave vector k = (0, 0.0817(6), 0) in the temp erature range 1.6 K-T-N = 22.6 K while for Dy2Co3Si5 a collinear antiferrom agnetic structure is observed between 1.5 K and T-N = 21.9 K, For R = Tb th e magnetic moment is parallel to the c-axis while for R = Dy it forms an an gle of 25.8 degrees with the c-axis. (C) 1999 Elsevier Science S.A. All rig hts reserved.