Magnetic Properties of DyPt3 and DyIn3

Abstract

Neutron-diffraction measurements made on powder samples of the intermetallic compounds, DyPt3 and DyIn3, show that these compounds exhibit antiferromagnetic ordering below Néel temperatures of 13.2° ± 0.3°K and 24° ± 0.5°K, respectively. The magnetic reflections from DyPt3 can be indexed on a doubled chemical cell of cubic symmetry. A suitable magnetic model consists of an arrangement where the Dy moments are aligned in opposite directions in adjacent (111) magnetic planes. For DyIn3, the magnetic reflections can be indexed on the doubled chemical cell of tetragonal symmetry. An appropriate magnetic model is one in which the Dy moments are aligned oppositely in adjacent (110) magnetic planes. The moment direction makes an angle of 27° ± 5° with the unique axis of the tetragonal magnetic cell. The saturated ordered moment is 9.0 ± 0.3 μB per Dy atom for DyPt3 and 8.8 ± 0.3 μB per Dy atom for DyIn3. The magnetic ordering process as a function of temperature closely follows a Brillouin function for DyPt3; the DyIn3 ordering shows a deviation from the customary behavior. The magnetic form factor data from the coherent magnetic reflections agree well between the two compounds but decrease faster with increasing scattering angle than theoretical predictions.