Influence of interchain coupling on the one-dimensional magnon Raman spectrum of CsCoBr 3

Abstract

Light scattering from magnons in CsCoBr 3 has been measured for temperatures well below the upper antiferromagnetic 3D ordering temperature of T l N = 28 K. These experiments reveal multiple magnon features of energies in the range 90 to 170 cm -1 similar to those found in CsCoCl 3 but previously unobserved for the bromide. Prominent features in the spectrum and their temperature dependence are described in terms of a recent theory by Shiba. Other, weaker features are explained by a simple extension of the theory to include fluctuations. A new band is observed at 178 cm -1, whose intensity drops sharply prior to the lower 3D ordering transition at T l N = 10 K. This band is assigned to magnon-phonon combination scattering.