The formation and migration energies of vacancies in quenched copper

High-quality copper single crystals have been quenched from temperatures between 750 and 10500C. The analysis of the quenched-in resistivities gives a vacancy formation energy of (1.27 +- 0.05)eV in good agreement with the monovacancy formation energy of (1.29 +- 0.02)eV found by positron annihilation. Isochronal annealing of quenched copper shows two recovery stages, one centred at 00C and one above 2000C. In the first stage, nearly 35% of the quenched-in resistivity is annealed out. Vacancies migrate in this stage with an activation energy of (0.74 +- 0.08)eV. The sum of the measured vacancy formation and migration energies is (2.01 +- 0.13)eV and agrees well with the monovacancy self-diffusion energy Qsub(SD)sup(1V) = (2.06 +- 0.05). The data can be explained within the vacancy annealing model for stage III in electron-irradiated copper as elaborated by Schilling and co-workers. Single vacancies migrate around 00C in Cu. They partially anneal at sinks and partially cluster to mobile divacancies and stable vacancy agglomerates which anneal above 2000C. (author)