Magnetic field and temperature dependent correlations in the singlet ground state system CsFeBr₃

Abstract

In the singlet ground state system CsFeBr₃ the temperature and magnetic field dependence of the magnetic dispersion curves have been measured by inelastic neutron scattering. At a field of 4.1 T magnetic Bragg peaks appear at (⅓ ⅓ 1) and (⅔ ⅔ 1).

The correlation lengths were derived from the experimental data by integrating the constant Q-scans over the energy transfer. The Q-dependence was fitted to Lorentzians and correlations lengths were extracted for different directions in the lattice. These correlation lengths decrease with increasing temperature and increase with increasing field. Above the phase transition the correlation lengths decrease again.