Magnetic Self-Recovery in Cold-Worked Copper

Abstract

FROM time to time many investigations have been carried out on the effect of cold-working on the magnetic properties of various metals¹, but there are still no very reliable conclusions to be drawn from the work. We have recently been making a comprehensive study of the effect of cold-working on the magnetic properties of pure metals, over a range of temperatures, and in the case of copper have observed evidence of a systematic change of magnetic susceptibility with time. This effect is most easily interpreted as a magnetic self-recovery or self-annealing of the metal, the observed susceptibility gradually approaching a stable value at a rate dependent on the temperature at which the metal is maintained. This effect appears to be related to X-ray observations which have recently shown that a self-recovery of cold-worked copper takes place fairly rapidly, even at room temperature^2,3,4.