The mean free paths of excess vacancies that were generated during electromigration were determined by using a combined electromigration/diffusion technique. The method was based upon the assumption that a steady-state excess vacancy distribution existed during electromigration. The latter was determined by measuring the diffusion enhancement of Cu in Ag at various positions along the electric field gradient. Under certain conditions, an evaluation of the measured diffusion enhancements by means of steady-state theory yielded the mean-square free paths of the excess vacancies. They were found to lie between 1.6 x 10-4 and 5.4 x 10-4cm2.

Measurement of Electrotransport-Induced Excess Vacancies in Silver J.Ruth: Journal of Physics - Condensed Matter, 1998, 10[13], 2901-14