Low dimensional magnetic systems often exhibit fascinating and subtle effects that are the low dimension analogues of the magnetism observed in the high temperature superconductors.
One-dimensional Heisenberg antiferromagnets exhibit a rich variety of dynamics especially at low values of spin where quantum fluctuations become important. Quantum theories of the magnetic excitations in the spin=1/2 systems predict a broad continuum of intensity above the classical spin wave dispersion. Although systems with a spin of 5/2 and greater are known behave to classically, materials such as CsVCl3 which have S=3/2 inhabit a crossover region between these two regimes.
By aligning the one-dimensional axis of the crystal perpendicular to the incident wavevector it is possible to map the entire spin-wave dispersion in a single measurement. In a five day experiment on MARI the dispersion curve for CsVCl3 was measured. The dispersion curve itself closely resembles the classical models for spin-waves - however, the width of the excitations is much broader than expected, indicating that the spin-wave damping is much larger than would be expected from classical theories.