Magnetic Energy Fluctuations: Observations by Light Scattering

Abstract
The first observations of magnetic energy fluctuations by light scattering are reported. The spectra observed in antiferromagnetic KNiF3 are strongly polarized, mildly q dependent, but strongly temperature dependent near TN=248.5 K. The observed line shapes exhibit two characteristic frequencies, one less than 0.6 GHz and the other between 5 and 15 GHz, depending on temperature.