Affiliation:
1. Department of Physics, Montana State University, Bozeman, MT 59717, USA
Abstract
It has previously been assumed that spin waves were the dominant excitations in lower-dimensional magnets. Recently, however, it has been shown that nonlinear excitations or solitons rather than spin waves influence the dynamic thermal quantities such as the spin correlation function which can be investigated experimentally through the electron paramagnetic resonance linewidth. In this review the influence of both spin waves and solitons on the temperature-dependent linewidth in the fluctuation region immediately above the ordering temperature is discussed. It is seen that both excitations result in a theoretical Arrhenius temperature-dependence, (∆H~ exp (E/T) where E=6πJs2 for spin waves and E=4πJs2 for solitons, J is the nearest neighbor exchange constant, and s is the value of the spin. In experiments, quantum (s=1/2) layered copper compounds exhibit the temperature dependence expected from spin waves even though nonlinear excitations have been shown to exist in these systems. On the other hand nearly classical (s=5/2) manganese compounds have the temperature dependence expected from solitons. The calculation of the linewidth from both spin waves and solitons is reviewed and compared with experimental data to show that solitons dominate the dynamics of the layered, nearly classical magnet.
Publisher
World Scientific Pub Co Pte Lt
Subject
Condensed Matter Physics,Statistical and Nonlinear Physics
Cited by
26 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献