Effect of a Magnetic Field on the Propagation of Sound Waves in a Ferromagnetic Material

Abstract

EXPERIMENTS in progress on the propagation of high-frequency longitudinal acoustic waves along a rod of ferromagnetic material have shown such waves to be influenced by the application of an external magnetic field in two ways. First, the velocity of propagation is modified, as is to be expected from the so-called ΔE effect in magnetostriction experiments, which refers to the change of Young's modulus with the applied magnetic field, and is of the order of a few per cent. Secondly, the attenuation of the waves is in general reduced as the applied field is increased, thus confirming the observations briefly noted by T. F. Rogers and S. J. Johnson¹.