Dynamics of longitudinal and transverse fluctuations aboveTcin EuS

Abstract
Using inelastic scattering of polarized neutrons near a finite Bragg reflection, the dynamics of longitudinal δS(q)∥q and transverse δS(q)⊥q spin fluctuations have been measured. The relaxation rates Γα follow rather precisely the dipolar dynamic-scaling function calculated recently by mode-coupling theory based on the Lorentzian approximation. The predicted longitudinal line shape near TC disagrees with our data.