The study of metal-oxide interfaces using sputter ion plating

The interface between solids has always been difficult to characterize. It is possible to use analytical techniques to probe through an outer surface but matrix effects within the penetrated solid often modify the results to the extent that the interface becomes difficult to detect. The progressive analysis and removal of layers of material from an outer surface until the interface is reached may prove useful but during the removal of thick outer layers the interface becomes indeterminate. A third approach is to dissolve one solid leaving the other intact, but again limitations are encountered. For example, only one side of the interface can be studied and the real boundary may be perturbed or damaged by the dissolving medium. Here we describe a new approach which may be used to study both the metal and oxide side of metal–oxide interfaces. Although this may at first appear to be a rather specialized application, the principles involved may be readily transferred to a number of other systems.