Temperature Dependence of Positron Trapping to Dislocations in Deformed Zinc

Abstract

Doppler-broadened lineshapes of positron annihilation in zinc have been measured as a function of temperature between 4.2 and 270 K after deformation and annealing up to various temperatures. The experimental results are well described in terms of a generalized trapping model where positrons become trapped in deep traps ( e.g. , jogs) via shallow traps (dislocation lines). It has been found that the positron trapping rate to the dislocation line decreases rapidly with increasing temperature up to about 80 K, whereas above 80 K the trapping rate is basically constant. The binding energy between a positron and a dislocation line has been shown to be about 50 meV.