title: Neutron study of the magnetism in NiCl2·4SC(NH2)2.
abstract: We study the strongly anisotropic quasi-one-dimensional S = 1 quantum magnet NiCl2·4SC(NH2)2 using elastic and inelastic neutron scattering. We demonstrate that a magnetic field splits the excited doublet state and drives the lower doublet state to zero energy at a critical field Hc1. For Hc1 < H < Hc2, where Hc2 indicates the transition to a fully magnetized state, three-dimensional magnetic order is established with the AF moment perpendicular to the magnetic field. We mapped the temperature/magnetic field phase diagram, and we find that the total ordered magnetic moment reaches m(tot) = 2.1 μB at the field μ(0)H = 6 T and is thus close to the saturation value of the fully ordered moment. We study the magnetic spin dynamics in the fully magnetized state for H > Hc2, and we demonstrate the presence of an AF interaction between Ni(2+) on the two interpenetrating sublattices. In the antiferromagnetically ordered phase, the spin-waves that develop from the lower-energy doublet are split into two modes. This is most likely the result of the presence of the AF interaction between the interpenetrating lattices.
authors: Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
authors: N
authors: N
authors: Tsyrulin
authors: C D
authors: CD
authors: Batista
authors: V S
authors: VS
authors: Zapf
authors: M
authors: M
authors: Jaime
authors: B R
authors: BR
authors: Hansen
authors: C
authors: C
authors: Niedermayer
authors: K C
authors: KC
authors: Rule
authors: K
authors: K
authors: Habicht
authors: K
authors: K
authors: Prokes
authors: K
authors: K
authors: Kiefer
authors: E
authors: E
authors: Ressouche
authors: A
authors: A
authors: Paduan-Filho
authors: M
authors: M
authors: Kenzelmann