Antiferromagnetism of ternary lanthanide stannides RAuSn (R=Pr, Nd, Gd-Er)

Neutron diffraction and magnetometric data show that hexagonal (LiGaGe-type crystal structure) RAuSn compounds (R = Pr, Nd, Gd, Tb, Dy, Ho) order antiferromagnetically at low temperatures. Their magnetic structures are described by the wavevector k = [1/2, 0, 0]; the magnetic moments are normal to the hexagonal axis in TbAuSn and DyAuSn, parallel to it in PrAuSn and HoAuSn and make an angle of 30 degrees in NdAuSn. ErAuSn is cubic (space group F (4) over bar 3m). At T = 1.6 K only a broad peak corresponding to short-range ordering is observed. The observed Neel points range from 2.8 K in PrAuSn to 24 K in GdAuSn. In all title compounds the magnitudes of ordered magnetic moments at 1.6 K derived from neutron diffraction experiments are smaller than the respective free R3+ ion values, indicating a strong effect of the crystalline electric field.