Vacancy diffusion in magnetite

The chemical diffusion coefficient in a single crystal of magnetite was measured by observing the relaxation of deviations from stoichiometry responding to a stepwise change in oxygen partial pressure between 1300 and 1450°C. The chemical diffusion coefficient was proportional to $\text{(?}\text{In}\text{δ}\text{?}\text{In}\text{p}{}_{\mathrm{o2}}\text{)}{}^{\mathrm{?1}}$. The vacancy diffusion coefficient was calculated with the help of nonstoichiometric data and was found to be independent of the vacancy composition. The value of D_v was

$\text{D}{}_{\mathrm{v}}\text{= (0.14 ± 0.08)}\text{exp}\text{(?}\text{(32,500 ± 1800)}\text{RT)}\text{cm}{}^2\text{s}{}^{\mathrm{?1}}$

.