Magnetic structure of Er6Ni2Sn

The crystallographic and magnetic structures of Er6Ni2Sn have been determined at low temperatures using neutron powder diffraction. It has been found that this system orders antiferromagnetically (AF) below TN = 17 K. Data taken at low temperatures and analyzed using symmetry group analysis suggest that Er6Ni2Sn forms a complex non-collinear commensurate AF structure with strongly reduced Er magnetic moments. The reason for the reduced moments is unclear and needs further studies. The magnetic phases below 7 K and in the temperature range 7-17 K differ only in the Er magnetic moment magnitudes and in the angle that the Er moments at the 8l site make with the c-axis. The extra reflections present in the powder diffraction patterns suggest presence of a secondary phase. The temperature evolution of the powder pattern indicates that the secondary phase orders AF at 35 K.