Generation and characterization of point defects in SrTiO3 and Y3Al5O12.

Positron annihilation lifetime spectroscopy (PALS) was applied to characterize point defects in single crystals of Y 3 Al 5 O 12 and SrTiO 3 after populating different types of defects by relevant thermal treatments. In SrTiO 3 , PALS measurements identified Sr vacancy, Ti vacancy, vacancy complexes of Ti–O (vacancy) and hydrogen complex defects. In Y 3 Al 5 O 12 single crystals the measurements showed the presence of Al-vacancy, (Al–O) vacancy and Al-vacancy passivated by hydrogen. These defects are shown to play the major role in defining the electronic and optical properties of these complex oxides. [ABSTRACT FROM AUTHOR]