The time-dependent behavior of the classical, ferromagnetic xy chain in a symmetry-breaking magnetic field was studied using a very fast, vectorized spin-dynamics method. The equations of motion were integrated using starting configurations determined by Monte Carlo simulations. By calculating spin-spin correlation functions and taking space-time Fourier transforms, we determined S(q,ω) for a wide range of fields and temperatures. We identify and measure the characteristics of single spin-wave peaks and two spin-wave sum peaks, as well as central peaks due to both soliton and two spin-wave difference processes. These results are discussed in light of existing theory and experiments.

• Received 24 July 1989

DOI:https://doi.org/10.1103/PhysRevB.41.7139