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

Abstract

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 • in NdAuSn. ErAuSn is cubic (space group F 43m). At T = 1.6 K only a broad peak corresponding to short-range ordering is observed. The observed Néel 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 R 3+ ion values, indicating a strong effect of the crystalline electric field. * Dedicated to Professor Henryk Szymczak on the occasion of his 60th birthday.

Magnetic and Mössbauer studies of the HoAuSn compound

“…The obtained lattice parameters are: a = 4.6221(3) Å; c = 7.3463(7) Å being in accord with those previously reported [3]. In contrast to the results obtained in [1,2] only one type of crystallographic structure appears for the HoAuSn sample independently on the heat treatment procedure used.…”

“…Such a reduction of the transition temperature under influence of an external magnetic field is also a characteristic feature for antiferromagnetic materials. Both results are close to the value estimated from neutron investigations (T N = 9) K [3]. Above 13 K, the temperature dependence of the magnetic dc susceptibility, as shown in paramagnetic Curie temperature Θ p = −7.7 K indicates AF interactions among Ho ions.…”

“…X-ray powder measurements confirmed that the diffraction pattern can be comparably well described either in terms of the hexagonal structure of CaIn 2 -type or its ordered derivative of LiGaGe-type [1][2][3], although a little better fit can be obtained for the last one, and this structure is also preferred from the analysis of neutron diffraction data [3]. The obtained lattice parameters are: a = 4.6221(3) Å; c = 7.3463(7) Å being in accord with those previously reported [3].…”

“…Among them, the title compound HoAuSn was investigated by bulk magnetic and neutron diffraction methods [3]. It was found that this compound orders antiferromagnetically at T N = 9 K and its magnetic structure is described by the wave vector k k k = [1/2, 0, 0] with the magnetic moment parallel to the hexagonal c-axis.…”

Mössbauer spectroscopic study of half-Heusler compounds

“…GdAuSn crystallizes in the hexagonal LiGaGe structure (P6 3 mc) [12], whereas MnAuSn crystallizes in the cubic half-Heusler AlLiSi structure F43m À Á . The difference of the atomic radii of Mn and Gd hinders an appearance of the solid solution between two compounds.…”