It is well known that diffusion in ionic materials occurs primarily by the movement of charged species. Therefore, an applied electric field can provide a very large driving force for mass transport. In the present study, thin films of In2O3 and Fe2O3 have been deposited on (001) and (111) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples have then been reacted in an applied electric field at elevated temperatures. The electric field directly influences the diffusion of the cations in the constitutive layers. Through the use of both transmission (TEM) and scanning (SEM) electron microscopy, diffusion couples reacted either with and without an electric field have been analyzed to examine the effect that an induced ionic current can have on solid-state reaction processes.

The apparatus for reacting the diffusion couples in a field has been described elsewhere. The diffusion couples were characterized in cross-section by SEM and TEM techniques.