Lead-free ferroelectric thin film with a composition of (K0.4425Na0.52Li0.0375) (Nb0.8825Sb0.08Ta0.0375)O-3 (KNLNST) has been successfully prepared on Pt/Ti/SiO2/Si substrate using sol-gel and spin-coating method. Polycrystalline perovskite films were obtained through pyrolysis at 400 degrees C and subsequent calcination at 700-800 degrees C for 30 min, which were optimized by means of X-ray diffraction and thermal analysis. The morphology on the top surface and fractured cross section of KNLNST films was observed by an atomic force microscope and a field-emission scanning electron microscope. Raman spectrum indicated that the film is almost stress-free as the film is thicker than 150 nm. The 300 nm-thick KNLNST film annealed at 750 degrees C exhibited a dielectric permittivity of 341, a loss tangent of 0.05 (1 kHz), a remanent polarization of 9.5 mu C cm(-2) and a coercive field of 31.8 kV cm(-1), as compared to the remanent polarization of 25.6 mu C cm(-2) and the coercive field of 10 kV cm(-1) for bulk ceramics. (C) 2011 Elsevier B.V. All rights reserved.