Positron Annihilation and Moessbauer Effect Studies of Im-Pb and Cu-Ni Binary Alloys

摘要

The alloy systems In(1-x)Pb(x) with x=0.00, 0.05, 0.20, 0.50, 0.80, 1.00 and Cu(1-x)Ni(x) with x=0.00, 0.10, 0.15, 0.17, 0.25, 0.30, 0.40, 0.60, 0.80 and 1.00 were studied using the positron annihilation method. Moessbauer spectroscopy was used for the In-Pb system studies. The composition dependence of the h parameter obtained from the angular distribution curves indicates a preferred annihilation of positron at the Pb atomic site in In-Pb alloys and at the Ni atomic site in Cu-Ni alloys. Additionally, temperature dependent measurements were carried out on In-20% Pb in order to evaluate the vacancy formation energy. The obtained value was 0.48 + or - 0.03 eV. The low momentum component (attributed to the contribution of the conduction electrons in the annihilation process) observed from the momentum distribution was correlated with the isomer shift obtained from the Moessbauer effect studies.