Structural relaxations at metal/metal oxide interfaces

In this paper work is reviewed on the structure of metal/metal oxide interfaces in model systems with well defined orientation relationships and boundary inclination. Structural relaxations established upon interface formation may be described as misfit dislocations which can be investigated using conventional and high resolution TEM. The conditions for obtaining informations at an atomistic scale using HRTEM are critically discussed. Specifically, geometrical restrictions are found to be critical in HRTEM study of [111] interfaces in fcc metal - fcc oxide systems. Different misfit dislocation networks at [100] interfaces in fcc metal - fcc oxide systems were observed which may be correlated to the relative strength of metal-anion and metal-cation bonds at the interface. In strongly interacting systems misfit dislocations can possess an equilibrium stand-off distance from the interface. In the system Nb-Al2O3 the interface is shown to be coherent by the registry of atomic columns adjacent to the interface. In this configuration energy is minimized by unbroken strong interfacial bonds and misfit localization in the elastically softer metal