Oxygen vacancy-transition metal-ion impurity association in SrTiO₃

The progressive reduction of SrTiO3 has been monitored by EPR. The results show the conversion of Mn4+ to Mn2+ and Mn2+ to Mn2+-V0 by oxygen-vacancy capture. The latter defect association takes place with the copious oxygen vacancies produced during high-temperature reduction between 1100 - 1300 K. At still higher reduction temperatures, other defects are formed. Analysis of the temperature dependence of the defect association gives a value of 0.7 eV for the enthalpy of association. © 1983.