Ultrasonic attenuation in the Heisenberg paramagnet

Abstract

Two models which describe the interaction between the spin system and the lattice are presented for examining the propagation of sound waves in ferromagnetic insulators. In particular, expressions for the ultrasonic attenuation coefficient at high temperatures and near the Curie point are obtained in terms of time-dependent correlation functions. The attenuation coefficient is found to be proportional to the square of the phonon frequency and to increase rapidly in the vicinity of the Curie point. © 1967 The American Physical Society.