Positron Lifetime Measurements on Electron Irradiated Amorphous Alloys

摘要

Great advance in understanding the nature of point defects in crystalline metals has been achieved by employing positron annihilation technique. Positrons detect vacancy-type defects and the lifetime value of trapped positrons gives information on the size of submicroscopic vacancy aglomerates and microvoids. In this paper it is shown that low-temperature electron irradiations can result in a considerable increase in the positron lifetimes in various amorphous alloys because of the formation of vacancy-like defects which, in addition of the pre-existing holes, are able to trap positrons. Studied amorphous alloys were Fe sub 80 B sub 20 , Pd sub 80 Si sub 20 , Cu sub 50 Ti sub 50 , and Fe sub 40 Ni sub 40 P sub 14 B sub 6 . Electron irradiations were performed with 3 MeV electrons at 20 K to doses around 10 exp 19 e exp - /cm exp 2 . After annealing positron lifetime spectra were measured at 77 K. (Atomindex citation 13:677581)