Neutron diffraction studies of the magnetic structures of HoAuGe and ErAuGe

Abstract The magnetic structures of HoAuGe and ErAuGe, both crystallizing in the hexagonal LiGeGa-type structure, have been investigated by high resolution neutron diffractometry in the temperature range between 1.5 and 7.7 K. For ErAuGe, additional low temperature diffraction experiments have been performed between 40 mK and 1.4 K. Both compounds order antiferromagnetically at low temperatures. The magnetic structure of HoAuGe at 1.5 K is described by a propagation vector k =[ 1 2 , 0, 0] . The low temperature diffraction pattern of ErAuGe is similar to that obtained for HoAuGe, however, some magnetic reflections of ErAuGe show a significant broadening. This broadening is due to a magnetic domain size effect. Transversal sine wave incommensurate magnetic structures appear close to the Neel temperatures. These structures can be described by a propagation vector k =[0.4461(5),0,0] at 4.5 K for HoAuGe and k =[0.4185(40),0,0] at 3.0 K for ErAuGe.