Ferroelectric and non-linear dielectric characteristics of Bi₀.₅Na₀.₅TiO₃ thin films deposited via a metallorganic decomposition process

Abstract

Polycrystalline Bi₀.₅Na₀.₅TiO₃ (NBT) thin films have been successfully fabricated via a metal organic decomposition process on Pt/Ti/SiO₂/Si substrates. The structural evolution of the as-prepared thin filmsannealed over the moderate temperature range 500–700 °C is studied. NBT thin filmsannealed at 700 °C are of single phase NBT perovskite type. They exhibit a well-defined P-E hysteresis loop at room temperature. The measured dielectric constant is 465–410 over the frequency range of 1 kHz to 1 MHz. The corresponding dielectric loss is ∼10⁻². The measured capacitance-voltage curve shows strong non-linear dielectric behavior leading to a high tunability of the dielectric constant, up to 14% at 1 MHz.J.X. acknowledges financial support from the Department of Education, Science and Training DEST in the form of an Endeavor Australian Research Fellowship Award. J.X., Y.L., and R.L.W. acknowledge financial support from the Australian Research Council ARC in the form of ARC Discovery Grants