HIGH-RESOLUTION ELECTRON-MICROSCOPY OF CU MGO AND PD/MGO INTERFACES/

Cu/(1 $($) over bar$$ 11)MgO and Pd/(1 $($) over bar$$ 11)MgO interfac es 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/(1 $($) over bar$$ 11) MgO and Pd/(1 $($) over bar$$ 11)MgO. In contrast to a previous work i n which cases the core structures of interfacial dislocations in Cu/(1 $($) over bar$$ 11)MgO and Pd/(1 $($) over bar$$ 11)MgO interfaces co uld not be directly observed from the high-resolution images, we have observed localized interfacial dislocations in both Cu/(1 $($) over ba r$$ 11)MgO and Pd/(1 $($) over bar$$ 11)MgO interfaces from high-resol ution images. Each interfacial dislocation in the Cu/(1 $($) over bar$ $ 11)MgO and Pd/(1 $($) over bar$$ 11)MgO interfaces actually contribu tes to sets of zig-zag dislocations in a hexagonal network. Viewing al ong [110], the overlapped distances of the zig-zag interfacial disloca tions in the network are similar to 0.5 and 1 nm for the Cu/MgO and Pd /MgO interfaces, respectively, which is comparable with the observed ' localized width' of interfacial dislocations from high-resolution imag es. The atomic structures of these two metal/oxide interfaces are dete rmined from through-focal series of high-resolution images. The termin ating lattice plane in the interface is the oxygen lattice plane for b oth Cu/(1 $($) over bar$$ 11)MgO and Pd/(1 $($) over bar$$ 11)MgO inte rfaces which are composed of distorted structural units of Cu2O and Pd O, respectively. Junction dislocations resembling those in grain bound ary facets, related to the difference of the rigid body translations, are observed between two energeticallty equivalent {1 $($) over bar$$ 11} 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.