Calorimetric Studies on Annealing Quenched-In Defects in Gold

Abstract

Energy evolved on annealing quenched-in defects in gold has been measured with a high-precision, fast-adiabatic microcalorimeter. The energy can be described by an equation, $\Delta E_T=B\exp (-\frac{E_f}{k{T}_Q})$, where $\Delta E_T$ is the total energy evolved for a quench from temperature, $T_Q$. $B$ is a constant equal to (4.5±1.0) × ${10}^4$ cal/g-atom. $E_f$, the energy of formation of the defect, is equal to 0.97±0.1 ev in good agreement with the value reported by Bauerle and Koehler from resistometric studies. The activation energy of motion of the defects has a temperature dependence confirming the results obtained resistometrically, i.e., $E_m=0.73\mathrm{} \mathrm{and} 0.62$ ev at $T_Q=820\mathrm{}°\mathrm{C} \mathrm{and} 920°\mathrm{C}$, respectively. Assuming that the quenched-in defects are single vacancies, the energy measurements can be combined with the resistivity data of Bauerle and Koehler to give the resistivity increase per one atomic percent vacancies, $\frac{\frac{\Delta {\rho }_0}{\Delta E_T}}{E_f}$, using only experimentally derived quantities. This ratio equals ${1.8}_0$±0.6 μohm cm/at.%. The volume increase of the gold lattice per vacancy determined from the ratio, $\frac{\frac{\Delta {\rho }_0}{\Delta E_T}}{E_f}$, and Bauerle and Koehler's relationship between resistivity and fractional volume change during recovery, is ${0.5}_7$±0.05 in good agreement with recent theoretical work of Tewordt.