High throughput physical vapour deposition and dielectric and ferroelectric screening of (Bi,Na)TiO3 thin-film libraries

Polycrystalline thin-film libraries of Bi2O3-TiO2-Na2O system have been synthesised over a wide composition region using elemental molecular beam epitaxy sources combined with an oxygen plasma source. Structural characterisation and the screening of both dielectric and ferroelectric properties of fabricated compounds have been carried out. The bismuth sodium titanate perovskite-type phases exhibited a high relative permittivity (up to 375), a loss tangent lower than 0.02 and ferroelectric properties superior to thin films synthesised using other deposition methods: a remnant polarization, Pr, approximately 22 μC/cm2 was observed in the optimal composition range. The high throughput approach allowed us to establish clearly the compositional boundaries of the ferroelectric perovskite phase in the system.