Abstract
Aluminum single crystals have been irradiated with 7.0-MeV protons at 20 K. The irradiation damage and its recovery are studied with positron-lifetime spectroscopy between 20 and 500 K. Stage-I recovery is observed at 40 K. At 240 K, loss of freely migrating vacancies is observed. Hydrogen in vacancies is found to stabilize the vacancies and prolong stage III to above 280 K, where the hydrogen bound to vacancies is released. Single and multiple occupancy of hydrogen atoms at monovacancies is put forward as the reason for the two recovery stages between 280 and 400 K. A binding energy of 0.53±0.03 eV is found for a hydrogen atom trapped at a monovacancy. The results are in excellent agreement with recent ion-beam-analysis results and also with theoretical estimates.
- Received 12 August 1986
DOI:https://doi.org/10.1103/PhysRevB.35.5524
©1987 American Physical Society