Homogenous pore-free Ba2NaNb5O15, KSr2Nb5O15, and 2 Na2O-PbO-6 center dot Nb2O5 were fabricated on sapphire substrates using the sol-gel technique. By controlling the gelation and coating process, thickness of thin films fabricated was controllable from -40 nm to -10 mu m. Synthesized thin films possessed highly preferred orientated microstructure. Another advantage of this method is the subsequent heat treatment temperature dramatically decreased compared with other methods. This increases stoichiometry control and makes the large scale fabrication more feasible and efficient. Published by Elsevier B V