In the search for new dielectric and ferroelectric compounds, we were interested in the perovskite (Sr1-xLax)(2)(Ta1-xTix)(2)O-7 solid solution with ferroelectric end members Sr2Ta2O7 (T-Curie = -107 degrees C) and La2Ti2O7 (T-Curie = 1461 degrees C). In order to achieve a Curie temperature close to room temperature, the formulation with x=0.01 was chosen and synthetized as thin films by reactive radio frequency magnetron sputtering. In oxygen rich plasma, a (Sr0.99La0.01)(2)(Ta0.99Ti0.01)(2)O-7 film is deposited, characterized by a band gap E-g = 4.75 eV and an (1 1 0) epitaxial growth on (0 0 1)MgO substrate. The use of nitrogen rich plasma allows to synthesize (Sr0.99La0.01)(Ta0.99Ti0.01)O2N oxynitride films, with band gap E-g similar to 2.10 eV and a polycrystalline, textured or epitaxial growth on (0 0 1)MgO substrate. Nitrogen-substoichiometric oxynitride films with larger lattice cells are produced for low dinitrogen percentages in the sputtering plasma. (C) 2014 Elsevier B.V. All rights reserved,