Date of Original Version
An unusual crossover mechanism has been discovered by numerical investigation of the dispersion spectrum of Heisenberg antiferromagnetic chains with various spin values in a magnetic field. This result is reflected in novel behavior of static properties such as the integrated intensity. A study of various excitation gaps using finite chain calculations extended by quantum Monte Carlo studies indicates unusual behaviour in the T=0 magnetization isotherms.
Jill C. Bonner, Gerhard Müller, M.P. Nightingale, H.W.J. Blöte and J.B. Parkinson. Heisenberg antiferromagnetic chains: quantum-classical crossover. J. Magnetism and Magn. Materials 54-57 (1986), 1253-1254.