THE POSITRON-DISLOCATION INTERACTION STUDIED IN DEFORMED ZINC SINGLE-CRYSTALS

The pyramidal dislocations and parallel basal dislocations induced from the deformation with compressive loading normal to the (0001) plane and to the (1012) plane of the Zn single-crystal specimen are observed by TEM. The positron lifetime experiments for the samples measured at 100 K yield two different trapping lifetimes. It is found that the lifetime tau d of positrons trapped and annihilated in basal dislocations lines increases by about 20% compared with that in bulk ( tau d=177+or-2 ps) and it is shown that a positron would be trapped in deeper traps (jogs) via the dislocation when the jog concentration along it is sufficiently high, with the annihilation lifetime close to that in a monovacancy. The intensities of the two trapping components decrease evidently with increase in temperature increasing to room temperature. The difference between positron-vacancy and positron-dislocation interactions are discussed.