Quasielastic neutron scattering has been utilized to investigate the Griffiths phase induced by an axial magnetic field in ${\mathrm{FeCl}}_2$ at temperatures ${\mathit{T}}_{\mathit{c}}$(H)⩽T⩽${\mathit{T}}_{\mathit{N}}$, where ${\mathit{T}}_{\mathit{c}}$(H) is the transition temperature in an external magnetic field H. We present the temperature dependence of the integrated neutron-scattering intensity at fixed scattering vectors for various magnetic fields. On cooling below ${\mathit{T}}_{\mathit{N}}$ the antiferromagnetic short-range fluctuations decrease due to an increase of the volume fraction which is already antiferromagnetically ordered. A weighted average of the local contributions to the antiferromagnetic susceptibility quantitatively describes the scattering cross section. © 1996 The American Physical Society.

• Received 1 March 1996

DOI:https://doi.org/10.1103/PhysRevB.54.9015