  Vacancy defects in thin film laser ablated SrTiO3 on SrTiO3 were identified
using variable energy positron annihilation lifetime measurements. Strontium
vacancy related defects were the dominant positron traps and, apart from in the
top ~ 50 nm, were found to be uniformly distributed. The surface layer showed
an increase in annihilation from larger open-volume defects, large vacancy
clusters or nanovoids.
