DEFECT CENTERS IN AS-GROWN, OXIDIZED AND REDUCED SrTiO//3:Co AND SrTiO//3:Mn.

The rich variety of defects found in SrTiO//3 for various heat treatments is described. This wide selection is typical for transition-metal ion-doped SrTiO//3, and is due to the ease of oxygen vacancy formation. The oxygen-vacancy associated centers are not all formed reversibly as in SrTiO//3, where the enthalpy of association of Mn2 plus -V//O were measured to be 0. 7 eV.