Magnetic structures of the CeScSi-type RZrSb compounds (R = Tb, Er)

Investigations made by neutron diffraction experiments on the RZrSb compounds (R = Tb, Dy, Ho and Er) are reported. These compounds crystallize in the tetragonal CeScSi-type structure (space group I4/mmm, No. 139). Below T-C (65 and 45 K for the Tb and DyZrSb compounds, respectively), the magnetic structure of both TbZrSb and DyZrSb compounds consists of ferromagnetic, (0 0 1) layers staked along the c-axis (mu(Tb) = 5.6(5) mu(B) and mu(Dy) = 4.6(5) mu(B) at 2 K). Below T-C = 22(2) K, the magnetic structure of the HoZrSb compound consists of a canted ferromagnetic structure with M, = 1.02(5) mu(B) (an antiferromagnetic arrangement takes place in the a direction), M-z = 5.01(8) B and M-total = 5.11(8) mu(B) at 2 K. Below T-N = 13 K, the ErZrSb compound adopts an incommensurate magnetic structure (antiferromagnetic) with a propagation vectors Q [+/- 0.1580(6), 0, 0) and a total moment value Of mu(Er) = 3.58(6) mu(B) at 2 K. The results are discussed and compared with those obtained for the closely related RTGe (R = Tb, Er, T = Ti, Mn, Ru) CeFeSi-type and CeScSi-type compounds. (c) 2004 Elsevier B.V. All rights reserved.