Temperature dependence of the rate of positron trapping by vacancies in gold

Abstract

Positron lifetimes were measured in high-purity gold in order to study the temperature dependence of the monovacancy-positron specific trapping rate, defined as the positron trapping rate per unit monovacancy concentration. In all cases a positive temperature dependence was found. Equilibrium experiments alone yielded a temperature dependence of ${T}^{0.5\ifmmode\pm\else\textpm\fi{}0.2}$ over the temperature range 673-1033 K. Experiments which combined quenching and equilibrium measurements indicated a temperature dependence of ${T}^{0.9\ifmmode\pm\else\textpm\fi{}0.1}$ between 243 and 1033 K. Additional measurements at lower temperatures indicated that a positive temperature dependence continues down to 115 K.