Magnetic interaction parameters from paramagnetic diffuse neutron scattering in MnO

Abstract

Magnetic interaction parameters are generally determined from magnon dispersion curves obtained by neutron inelastic-scattering experiments in the ordered phase at low temperature. At higher temperature, above the phase transition, the parameters have to be extracted from the diffuse scattering distribution. Using a mean field theory extended by an Onsager reaction term we demonstrate that the interactions can also be determined in the paramagnetic phase. The theory describes well the paramagnetic phase of MnO in a large temperature range from 130 to 220 K.