Magnetic neutron scattering investigation of the field-induced Griffiths phase in FeCl2

TL;DR

This study uses quasielastic neutron scattering to explore the field-induced Griffiths phase in FeCl2, revealing temperature-dependent magnetic fluctuations and the evolution of antiferromagnetic order under external magnetic fields.

Contribution

It provides a detailed analysis of the Griffiths phase in FeCl2 using neutron scattering, highlighting the temperature and field dependence of magnetic fluctuations and order.

Findings

Antiferromagnetic fluctuations decrease below TN with increasing ordered volume.

The scattering cross section is well described by a weighted average of local susceptibilities.

Temperature dependence of scattering intensity varies with magnetic field.

Abstract

Quasielastic neutron scattering has been utilized to investigate the Griffiths phase induced by an axial magnetic field in FeCl2 at temperatures Tc(H)<=T<=TN, where Tc(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 TN 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.