MAGNETIC-STRUCTURE OF TBAGSN AND HOAGSN

Polycrystalline TbAgSn and HoAgSn have been studied by neutron diffraction. The data obtained at 300 K do not discriminate between the possibilities of the crystal structure being described as (i) the space group P6(3)/mmc (CeIn2 type) with Ag and Sn atoms distributed at random or (ii) by P63mc (GaGeLi type) with an ordered distribution of Ag and Sn. Both compounds order antiferromagnetically: TbAgSn below 33 K and HoAgSn below 15 K with magnetic moments at 4 K of 8.5(1) and 8.8(1) K, respectively. The moments are aligned along the hexagonal axis of the magnetic cell with the dimensions: a(m) = a(c), b(m) = a(c) square-root 3, c(m) = c(c), where a(c) and c(c) are the parameters of the crystallographic unit cell.