Evidence is presented for the trapping of positive muons at monovacancies and divacancies in quenched aluminum. The annealing of vacancies as sensed by the muon-spin-rotation effect is compared to positron annihilation measurements on identically prepared samples, showing that whereas positrons are trapped primarily at small vacancy clusters, muons are trapped mainly at monovacancies and diavancancies. Furthermore, the data indicate that it may be possible to study monovacancies and divacancies separately with the muon-spin-rotation technique.

• Received 14 May 1979

DOI:https://doi.org/10.1103/PhysRevLett.43.1513