Magnetomechanical Damping in the Temperature Range of 78°–300°K

Abstract

The damping of mechanical vibrations associated with the stress induced movement of magnetic domain boundaries was measured in pure nickel, pure iron, and in an iron-3.7% silicon alloy over the temperature range of 78°–300°K. The damping was characteristically amplitude dependent with maximum values at specific values of the shear strain. The damping for nickel, as expressed by the fractional energy loss per cycle, had maxima that decreased from 0.58 at 78°K to 0.36 at 300°K. The damping maxima for iron decreased only slightly from 0.20 at 78°K to 0.16 at 300°K. However, in the case of the iron-3.7% silicon alloy the damping maxima increased from 0.19 at 78°K to 0.28 at 300°K. The results are discussed in terms of the recently proposed mathematical model of magnetomechanical damping by Smith and Birchak. Much of the variation of the damping with temperature can be accounted for by variations of the magnetostriction with temperature.