Effect of BNBTKNN on the electrical properties of bismuth ferrite thin films

BiFeO3/[0.93(Bi0.50Na0.50TiO3)–0.05BaTiO3–0.02K0.50Na0.50NbO3] (BFO/BNBTKNN) bilayered thin films were fabricated on Pt/TiO2/SiO2/Si substrates without any buffer layers by a combined sol–gel and radio frequency sputtering route. Effect of BNBTKNN on electrical properties of BFO/BNBTKNN thin films was investigated. A higher phase purity and a denser microstructure are induced for the BFO/BNBTKNN bilayered thin film by using the bottom BNBTKNN layer, resulting in its lower leakage current density. Moreover, the enhancement in dielectric behavior is also demonstrated for such a bilayer, where a high dielectric constant and a low dielectric loss are obtained. The BFO/BNBTKNN bilayered thin film has an improved multiferroic behavior: 2Pr ∼ 76.8 μC/cm2, 2Ec ∼ 378.1 kV/cm, 2Ms ∼ 52.6 emu/cm3, and 2Hc ∼ 453.6 Oe, together with a low fatigue rate up to ∼1 × 109 switching cycles.