Time-differential perturbed-angular-correlation studies of radiation damage with radioactive probes implanted in cubic metals

The direct "microscopic" study of radiation damage by means of time-differential perturbed-angular-correlation measurements with implanted radioactive probes is shown to be a promising new technique. First results are reported for the fcc metals Cu, Al, and Pt. The radioactive probe ${}_{}{}^{111}{}_{}{}^{}\mathrm{In}$ was implanted by use of an electromagnetic isotope separator at an energy of 80 keV. The radiation damage studied was that produced by the ion implantation itself. After implantation at 24 K essentially 100% of the probe nuclei experience a distribution of strong electric field gradients due to nearest-neighbor defects. After implantation at 293 K in most cases dominant fractions are influenced by further distant radiation damage. In general, after annealing the interaction patterns changed. In one case (Pt) the measurements revealed the trapping of a single defect by the implanted impurity. This defect-ion pair was destroyed again after annealing at 673 K. The defect is interpreted as a single vacancy.