High-resolution electron microscopy of Cu/MgO and Pd/MgO interfaces

Cu/(111)MgO and Pd/(111)MgO interfaces with a cube-on-cube relation are produced by the internal oxidation technique. High-resolution transmission electron microscopy has been applied to study the interface structures of Cu/(111)MgO and Pd/(111)MgO. In contrast to a previous work in which cases the core structures of interfacial dislocations in Cu/(111)MgO and Pd/(111)MgO interfaces could not be directly observed from the high-resolution images, we have observed localized interfacial dislocations in both Cu/(111)MgO and Pd/(111)MgO interfaces from high-resolution images. Each interfacial dislocation in the Cu/(111)MgO and Pd/(111)MgO interfaces actually contributes to sets of zig-zag dislocations in a hexagonal network. Viewing along [110], the overlapped distances of the zig-zag interfacial dislocations in the network are {most positive}0.5 and 1 nm for the Cu/MgO and Pd/MgO interfaces, respectively, which is comparable with the observed 'localized width' of interfacial dislocations from high-resolution images. The atomic structures of these two metal/oxide interfaces are determined from through-focal series of high-resolution images. The terminating lattice plane in the interface is the oxygen lattice plane for both Cu/(111)MgO and Pd/(111)MgO interfaces which are composed of distorted structural units of Cu₂O and PdO, respectively. Junction dislocations resembling those in grain boundary facets, related to the difference of the rigid body translations, are observed between two energetically equivalent {111} facets in the Cu/MgO and Pd/MgO interfaces. The Burgers vector of the junction dislocation is 1 6〈112〉 and a stacking fault in the soft metal matrix is found accompanying this junction dislocation. © 1994.