Papers by Keyword: Positron Trapping

Abstract: Positron annihilation lifetime spectroscopy combined with Doppler broadening of annihilation radiation was applied to study free-volume entities in GeS₂-Ga₂S₃ glasses affected by Ga additions. It is shown that Ga-related void sub-system plays a decisive role in positron trapping process, while the overall density variation is defined mainly by Ge-related sub-system. These results serve as basis for new characterization route for inner free-volume structure of these glasses.

Abstract: Planar defects may exhibit free volumes which, in principle, are detectable using positron annihilation spectroscopy. In this contribution, we present a preliminary theoretical study of positron trapping at stacking faults in zinc oxide and at a grain boundary in zirconia. In particular, we calculate the positron lifetime and positron binding energy to such defects. In the case of the grain boundary in zirconia, the influence of the yttrium segregation on the GB structure and positron characteristics is also examined. Calculated structural and positron characteristics are critically compared with experimental and other calculated data.