A channelling study of defect-impurity complexes in proton irradiated molybdenum (cobalt)

Channelling experiments have been performed to determine the configuration of impurity-defect configurations in MoCo after irradiation with 600 keV protons at 50 K. Proton Induced X-ray Excitation (PIXE) was used to identify the Co impurities. It is shown that the Co atoms can be displaced from substitutional lattice sites by the trapping of interstitial atoms that are mobile at the irradiation temperature. Experimental angular scans were compared with detailed Monte-Carlo calculations. The fluence dependence was investigated for two samples with mean impurity concentrations of 2 x 10-3 and 5 x 10-3. The experiments are compatible with the concept that the trapping of a single interstitial leads to the formation of <110>-mixed dumbbells and the trapping of a second interstitial leads to a displacement of the Co impurity into the <100>-direction. (orig.)