Magnetic damping in gadolinium

Abstract

The variation of internal friction with strain amplitude at temperatures of 115, 168, 215, 245 and 298°K has been measured using a torsional pendulum at a frequency of 1 c/s. The damping with a magnetic origin has been separated from the total damping by a method due to Granato and Lucke, and the results have been explained in terms of the irreversible movement of 90° domain boundaries. A simple analysis using domain theory predicts a relation between the stress at peak damping and the magnetic field at maximum susceptibility. For gadolinium this field is 006 Oe at 245°K. A simple treatment of the variation of peak damping with temperature shows qualitative agreement with the results.