The defect chemistry and transport properties of monocrystalline 9.5mol%Y2O3-stabilized ZrO2, which was selectively doped with 3d transition-metal or rare-earth ions, were analyzed. In situ and ex situ electron paramagnetic resonance (electron spin resonance) and optical absorption spectroscopy were used to quantify the concentrations of redox-active ions in specific valence states as a function of temperature and O partial pressure, and to measure the chemical diffusion of O. Relevant self-consistent defect equilibrium constants (O incorporation, dopant-ion ionization) and transport coefficients (mobilities of electrons, holes and O vacancies) were deduced. The analysis exploited the significance of trapping effects for the thermodynamic factor of O, and the fact that the activity coefficient of O vacancies - although non trivial - did not depend upon the O partial pressure or minor redox-active impurities.

Re-Analysis of Defect Equilibria and Transport Parameters in Y203-Stabilized ZrO2 Using EPR and Optical Relaxation. K.Sasaki, J.Maier: Solid State Ionics, 2000, 134[3-4], 303-21