Specific Heat ofCsNiF3: Evidence for Spin Solitons

Abstract
The specific heat of the linear-chain magnet CsNiF3 has been measured at temperatures between 4 and 18 K, in magnetic fields up to 8 kG (0.8 T). A rounded peak is observed in both the temperature and field dependence. The peak positions in the field dependence are in qualitative agreement with classical soliton theory and they are also consistent with neutron-scattering estimates of the soliton rest energy. Quantitative comparisons indicate the need for extensions of the theory.