Magnetic Properties of $TbNi_{1-x}Au_{x}In$ Compounds

Polycrystalline samples of $TbNi_{1-x}Au_{x}In$ for x = 0.1, 0.2, 0.4, 0.6 and 0.8 were prepared and studied by powder X-ray and neutron diffraction and ac magnetic susceptibility measurements. These compounds crystallize in the hexagonal ZrNiAl-type structure. With increasing Au content a change in the magnetic structure is observed. For x = 0.1, 0.2 and 0.4 the magnetic order is described by the propagation vector k = (1/2, 0, 1/2) while for x = 0.8 by k = (0, 0, 1/2). Between 1.5 K and the Néel temperature the magnetic order is stable.