Solitons in the paramagnetic and partially disordered phases ofCsCoCl3

Abstract

We present a detailed quantitative experimental analysis of the soliton regime in a one-dimensional (1D) quantum spin system. The experiments were performed on the 1D antiferromagnet ${\mathrm{CsCoCl}}_3$. As well as soliton fluctuations, a 1D antiferromagnetic mode was observed in both the paramagnetic (T>$T_{N1}$≃21 K) and the partially disordered (T<$T_{N1}$) phases. This result proves that, below $T_{N1}$, one third of the chains remains in a paramagnetic state with fluctuations governed by solitons. In a semiphenomenological model the collisions between solitons are explicitly taken into account in our description, yielding good agreement between theory and experiment over the whole temperature range.