Nonstoichiometry in General

For the acceptor-doped BaTi03 with the lattice molecular formula of Eq. (16), the nonstoichiometry has been given as Eq. (20) or 

When the concentration of trapped holes is no longer negligible compared to that of the free holes, it is possible to rewrite Eq. (40), due to the mass conservation constraint, Eq. (34), and the charge neutrality constraint, Eq. (18), as  

The latter is the oxygen activity corresponding to8=0orn = p(l+% ) (see Figpre 10.5). At this specific oxygen activity the variation P8 as a function of In ooz 

This fact actually provides a means to locate the stoichiometric point on a nonstoichiometry isotherm that is measured [18]. 

Equation (46), in association-with Eq. (3), indicates that K i = n(p + [A ]) thus, the latter may be termed the pseudo-equilibrium constant for intrinsic electronic excitation. It is noted that only when 0. K i Ki and Eq. (45) takes the 

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