Non-stoichiometric Mn-doped Gd2(Ti0.975Mn0.025)2O7 was studied, as a function of temperature and O partial pressure, by using an O titration cell. Analysis of the data showed that the defect equilibrium could be explained by assuming that the predominant point defects were neutral O interstitials, doubly-charged O vacancies, and trivalent and quadrivalent Mn ions that were substituted at Ti sites.

O.Porat, H.L.Tuller: Journal of the American Ceramic Society, 1996, 79[12], 3078-82