Application of Moments to Light Scattering in Antiferromagnets

Abstract
Measurements on two-spin fluctuation light scattering in MnF2 have been obtained over the temperature range 2-300°K; the results are in good agreement with a theoretical analysis based on frequency moments and intensity of the scattering spectra. We find that the first moment shows critical-type behavior in the vicinity of the Néel temperature TN and that the measured high-temperature second moment allows a determination of the antiferromagnetic exchange constant in the paramagnetic phase.