The influence of structure disorder on mean atomic momentum fluctuations and a spin-wave spectrum

Abstract

The relation between atomic momenta fluctuations and density fluctuations is obtained in frames of mean-field approximation. Using two-time temperature Green functions within Tyablikov approximation the equations for spin excitation energy and damping are obtained. The asymptotics of energy and damping in the long-wave limit are investigated and the anomalous behaviour of spin-wave stiffness constant is discussed.Comment: 5 Latex pages, to appear in JMM