A positron lifetime study of lanthanum and niobium doped Pb(Zr _0.6Ti_0.4)O₃

A study of vacancy-related defects in lanthanum and niobium doped PbZr _0.6Ti_0.4O₃ with dopant concentrations of 0-6 and 0-4 mol%, respectively has been performed using positron annihilation spectroscopy X-ray diffraction, and photoelectron spectroscopy. Positron lifetime as well as coincidence annihilation radiation Doppler line broadening measurements were carried out. It was found that the samples exhibit vacancy like defects that act as positron traps. Two main defect lifetime components were found in both sample sets one at ≈ 150 ps and one at ≈ 300 ps. These defect trapping sites can be attributed to single oxygen vacancies and A-site vacancies, respectively. Doppler line broadening measurements, however, do not show significant changes as a function of dopant concentrations in terms of shape S and wing W parameters.