Magnetic structures of the CeScSi-type RZrSb compounds (RÂ =Â 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 TC (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 (μTb = 5.6(5) μB and μDy = 4.6(5) μB at 2 K). Below TC = 22(2) K, the magnetic structure of the HoZrSb compound consists of a canted ferromagnetic structure with Mx = 1.02(5) μB (an antiferromagnetic arrangement takes place in the a direction), Mz = 5.01(8) μB and Mtotal = 5.11(8) μB at 2 K. Below TN = 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 μEr = 3.58(6) μB 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.