Neutron diffraction studies of rare earth compound Nd7Ni3 in an external magnetic field

Neutron diffraction experiments were carried out to determine the magnetic structure of Nd7Ni3 in an external field. At 4.2 K and in external fields b elow 1.3 T the magnetic structure is conical with a basal plane helical com ponent having a propagation vector Q = (0, 0, 1/3) and a c-axis ferromagnet ic component. Above 1.3 T the c-axis component disappears, while the basal plane component remains up to 2.7 T. Below 0.3 T, the magnetic structure ch anges from conical to helical at about 8 K. A rough (H, T) phase diagram is given and is generally consistent with the results of magnetization measur ements. (C) 1999 Elsevier Science Ltd. All rights reserved.