Non-linear excitations in antiferromagnetic chains

Recent theoretical and experimental results on non-linear excitations in one dimensional classical antiferromagnetic chains are reviewed with a particular emphasis on dynamic properties. The main investigated substance is TMMC which can be regarded as a quasi-one-dimensional antiferromagnet with easy plane anisotropy. A discussion of Haldane's conjecture that there is an excitation gap for integer, but not half-integer spin is given. The open questions and possible investigation for the future are discussed. (author)