Perovskite lanthanum niobate and tantalate thin films prepared by sol–gel method

Perovskite lanthanum niobate La1/3NbO3 (LN), tantalate La1/3TaO3 (LT) and La1/3Nb0.8Ta0.2O3 (LNT) thin films (~150nm thickness) were prepared for the first time by sol–gel/spin-coating process on Pt/SiO2/Si substrates and annealing at 1100°C. The novel precursors of films were synthesized using Nb- or Ta-tartrate complexes. XRD analyses confirmed that the LT possessed a single perovskite tetragonal La0.33TaO3 phase, while LN or LNT films contained perovskite orthorhombic La1/3NbO3 or tetragonal La1/3TaO3 and traces of secondary pyrochlore LaNb5O14. The spherical and needle-like particles in heterogeneous microstructure of LN and LNT films and presence homogeneous transparent clusters of spherical nanoparticles in LT were observed. [Display omitted] •La1/3(Nb,Ta)O3 films were prepared by modified sol–gel/spin-coating process.•Precursors of films were synthesized from novel Nb and Ta-tartrate complexes.•Perovskite La1/3NbO3 and La1/3TaO3 phase were confirmed after annealing at 1100°C.•Two perovskite and pyrochlore LaNb5O14 were identified in La1/3Nb0.8Ta0.2O3 films.•Transparent La1/3TaO3 film of 150nm thickness contained pure perovskite phase.