Abstract
Using thermal neutron scattering techniques, the development of magnetic ordering in single-crystal DHCP praseodymium has been studied over the temperature range 0.03-4.2K. The intensity of the broad elastic peak around the wavevector 0.11 tau 100 (which has been observed in previous studies of Pr) increased steadily as the temperature was reduced. In addition, new satellite reflections originating from a sinusoidally modulated magnetic structure with wavevector 0.13 tau 100 were observed at temperatures well below 1K. The magnetic transition is believed to be driven by an enhancement of the exchange interaction via the hyperfine interaction. No temperature dependence of the magnetic excitation energies between 4.2K and 0.03K was detected.