Theoretical and experimental results were reported for film/substrate interface energies and misfit accommodation in Pt thin films on (001)MgO. Two epitaxial orientations were observed in Pt films which had been deposited onto (001) MgO substrates by means of electron beam evaporation. One of these was [110](001)Pt||[110](001)MgO, while the other was [110](111)Pt||[110](001)MgO, and O-lattice calculations were used to predict the film/substrate interface structure and relative interfacial energy for each orientation. It was assumed that the interfacial energy was due only to the elastic energy of the misfit dislocations. The [110](001)Pt||[110](001)MgO orientation was predicted to have the lower interfacial energy, and a deep minimum in the elastic interfacial energy function was found for the experimentally observed in-plane alignment of the (001)-oriented Pt. The minimum-energy Pt/MgO interface was composed of a square network of Pt edge dislocations with Burger’s vectors of the form: 1/2<110>. The interfacial dislocation structure which was predicted by the use of O-lattice calculations, for the case of the [110](001)Pt||[110](001)MgO orientation, was confirmed by using weak-beam electron microscopy. An interfacial energy minimum was also calculated for the perfect [110]Pt||[110]MgO in-plane alignment of (111)-oriented Pt on (001)MgO. This was in accord with experimental observations. The low-energy interfacial dislocation structure which was predicted for this orientation was a rectangular net of pure edge dislocations with Burger’s vectors of the form: 1/2<110> and 1/2<11¯2>. It was found that the calculated relative interfacial energies of the various epitaxial film orientations were consistent with observed trends in orientation selection.

P.C.McIntyre, C.J.Maggiore, M.Nastasi: Acta Materialia, 1997, 45[2], 869-78