Anisotropic Magnetic Fluctuations in the 3-K Antiferromagnets

Abstract

The anisotropy of magnetic fluctuations propagating along the high-symmetry directions in cubic systems with 3-k magnetic order is analyzed within the random-phase approximation assuming anisotropic exchange interactions. Both transverse and longitudinal structures are considered, with reference to the UO2 and USb compounds, respectively. In the case of UO2, the spin-waves polarizations calculated for acoustic and optical branches are favorably compared with three-dimensional polarization analysis experiments carried out on a triple axis spectrometer. The overall spin-waves polarization behavior emerges as a consequence of the 3-k nature of the magnetic order, whatever the strength of the exchange coupling assumed.