The aim of this work is to obtain films with suitable characteristics for use as buffer layers for YBCO superconducting electrodes in LiNbO3-based electro-optic devices. For this purpose, an epitaxial buffer with single orientation and low surface roughness is required. The possibilities of two oxides, yttria-stabilised zirconia (YSZ) and CeO2, have been explored. The films were grown on X-cut LiNbO3 single crystals by pulsed laser deposition, and the influence of the processing conditions was studied. The YSZ films are epitaxial with single (0 0 1) orientation and the surface is appropriate for use as a first layer in a heterostructure. These were the properties found in films grown under relatively broad ranges of deposition parameters, which allows a very high reproducibility. However, the lithium-deficient LiNb3O8 compound was found at the interface in all the films. This compound was not observed when CeO2 films were deposited. These films are epitaxial and (0 1 1)-oriented, although they can also contain (0 0 1)-orientated crystals. (C) 2002 Elsevier Science B.V. All rights reserved.