An X-ray diffraction study was made of Cu3Ba2YO7 films which had been deposited onto (001) AlYO3 substrates by means of metalorganic chemical vapor deposition. A twinning orientation between film and substrate was compared to that which was observed for films which were deposited onto (001) MgO, (001) SrTiO3 or (012) AlLaO3 substrates. Analysis of hhl-type reflections, and grazing incidence X-ray diffraction studies of the 020/200 reflections of Cu3Ba2YO7, revealed a particular epitaxial relationship on AlYO3 in which there was only one twinning direction relative to the substrate. The [110] and [1¯10] directions of Cu3Ba2YO7 were aligned with the [010] direction of AlYO3. This twinning geometry was explained in terms of coherency strains.

C.Dubourdieu, J.P.Sénateur, O.Thomas, F.Weiss, B.P.Thrane, M.Brunel: Applied Physics Letters, 1996, 69[13], 1942-4