Ferroelectric crystals such as Lead Zirconate Titanate (PZT) exhibit piezo-electric, pyro-electric and electro-optic coefficients that are several factors higher than non-ferroelectric crystals. When considering optical applications such as high-speed electro-optic modulators it is vital to have a deposition technique that can grow thin films with high quality on the desired substrate. Epitaxial growth is not always a necessity and preferentially oriented polycrystalline films are often sufficient. In our work we demonstrate that we are able to deposit different types of preferentially oriented thin ferroelectric films on any substrate which can withstand the annealing temperature of the thin films of 500 to 600 °C, including silicon, glass, silicon nitride, etc. The key factor in this deposition is the use of an intermediate layer which acts both as seed and buffer layer. It is found that lanthanide based intermediate layers as thin as 10 nm result in high quality films with strong remnant polarization and low dielectric losses. Measurements of the electro-optic coefficients of these films are performed using ellipsometry. Depending on the lanthanide used for the buffer layer (La, Pr, Nd, Sm) the effective electro-optic coefficient ranges between 150 and 300 pm/V. Such high electro-optic coefficients are interesting for high speed electro-optic modulators. Currently electro-optic modulators are being fabricated based on silicon-on-insulator nano-photonic waveguides with a PZT cladding.