Thermal-Equilibrium Properties of Vacancies in Metals through Current-Noise Measurements

We report a new method of measuring thermal-equilibrium properties of vacancies in metals through current-noise measurements. Aluminum noise spectra taken at 435 and 475°C directly yield vacancy lifetimes ${\tau }_0=4.7\mathrm{}\times {10}^{-3\mathrm{}} \mathrm{and} 2.8\times {10}^{-3\mathrm{}}$ sec, respectively, corresponding to a migration energy $E_m=0.6\mathrm{}$ eV, and permit estimation of a unit vacancy resistivity $\Delta {\rho }_v=1.9\mathrm{}\times {10}^{-8\mathrm{}}$ Ωm/at.% from the measured product ${\left(\Delta {\rho }_v\right)}^2{\eta }_v$, ${\eta }_v$ being the vacancy concentration taken from literature data.