Demystification of Mizusaki’s α-factor for the positively-deviated defect behavior of hyperstoichiometric oxides
March 10-14, 2019
Many hyperstoichiometric (p-type) ternary or higher oxides of present technological interests, e.g., La1-xSrxCrO3-δ exhibit a positive deviation from the ideal defect structure. Mizusaki et al.  could beautifully explain the positively-deviated defect structure by introducing an empirical factor α such as
Here, ΔHxs stands for the excess enthalpy of oxidation reaction involving oxygen vacancies and holes or
1/2 O2+VO••=OOx+2h• .
The authors interpreted this α-factor as representing the interactions among lattice ions and defects, but its true physico-chemical face has since remained a mystery notwithstanding so frequent invoking to the defect chemistry stage.
It has recently turned out that this factor corresponds to the first order approximation of the hole-degeneracy effect. We will demystify this α-factor in this line.
 J. Mizusaki, S, Yamauchi, K. Fueki, and A. Ishikawa, “Nonstoichiometry of the perovskite-type oxide La1-xSrxCrO3-δ,” Solid State Ionics 12 (1984) 119.
H.-I. Yoo and J. Mizusaki, "Demystification of Mizusaki’s α-factor for the positively-deviated defect behavior of hyperstoichiometric oxides" in "Nonstoichiometric Compounds VII", ECI Symposium Series, (2019). https://dc.engconfintl.org/nonstoichiometric_vii/29