Effect of Internal Stress Distribution on Magnetomechanical Damping

Abstract

Magnetomechanical damping in ferromagnetic materials has its source in stress-driven irreversible movement of magnetic domain boundaries. The maximum damping is proportional to λsE/σi, where λs is the saturation magnetostriction, E is Young's modulus, and σi is the average internal stress opposing domain boundary motion. In order to obtain the stress dependence of the damping, we include a distribution of internal stresses over a range ±Δσi about the average value. Inclusion of this distribution yields a theory in good quantitative agreement with experimental results for samples of 4% Si–Fe and cast iron.