Films which were oriented along the a-axis or b-axis were grown onto NdGaO3 substrates by means of liquid-phase epitaxy; using both horizontal and vertical dipping techniques. The use of polarization microscopy and X-ray diffraction methods revealed the existence of orthorhombic twin domains with an a-axis or b-axis orientation. By using atomic force microscopy, trains of macro-steps were observed. In the case of optically smooth surfaces, atomic force microscopy revealed growth steps with heights of 0.37 or 0.68nm (and integer multiples of these values). High-resolution transmission electron microscopy demonstrated the perfection of the crystal lattice in the near-substrate region, which was disturbed only by a few stacking faults. The measured lattice parameter, c = 1.36nm, in the region of a stacking defect corresponded to one Cu4Ba2YO8 unit, and implied the incorporation of an additional CuO plane.

C.Dubs, S.Bornmann, M.Schmelz, T.Schüler, F.Sandiumenge, G.Bruchlos, P.Görnert: Journal of Crystal Growth, 1996, 166, 836-40