NEUTRON-DIFFRACTION STUDIES OF RARE-EARTH COMPOUND, ND7NI3

Powder neutron diffraction on the hexagonal compound Nd,Ni, have been performed from 35 to 1.7 K. The magnetic structure is conical at 1.7 K , with a basal plane helix with propagation vector k = (0, 0, 1/3), an d a c-axis ferromagnetic component. Above 8 K, the c-axis ferromagneti c component disappears, while the basal plane helical component remain s up to the Neel temperature at 25 K. The propagation vector changes f rom k = (0, 0, 1/3) at 1.7 K to k = (0, 0, 0.257) at 20 K through a tw o-phase state with k = (0, 0, 0.286) and k = (0, 0, 0.314) at 7.25 K. (C) 1998 Elsevier Science B.V. All rights reserved.