%0 Journal Article %A D.J Keeble %A A Krishnan %A T Friessnegg %A B Nielsen %A S Madhukar %A S Aggarwal %A Ramamoorthy Ramesh %A E.H Poindexter %B Applied Physics Letters %D 1998 %G eng %P 508-510 %R 10.1063/1.121916 %T Vacancy defects in thin-film La0.5Sr0.5CoO3-δ observed by positron annihilation %V 73