Role of rapid and slow cooling on leakage mechanism and ferroelectric polarization of sputtered epitaxial BiFeO3 thin films

Abstract Epitaxial BiFeO 3 thin films with a (00 l ) orientation were grown on SrRuO 3 -coated LaAlO 3 substrates via magnetron sputtering. A coexistence of dominant rhombohedral (R) phase with a small amount of tetragonal (T) phase was identified by XRD. The cooling speed did not affect the film's growth orientation and phase structure, while it showed a notable influence on ferroelectric polarization and leakage mechanism. It was shown that the improved electrical properties, e.g. a low dielectric loss (tanδ  J −4 A/cm 2 ), as well as an enhanced polarization of 2 P r  ∼ 135 μC/cm 2 with a reduced coercive field of 2 E c  ∼ 373 kV/cm, were achieved in the BiFeO 3 thin film prepared via a slow cooling speed (∼6 °C/min in present case), which could be attributed to its fully crystallization without any impurity phase and well-developed microstructure at a slow cooling environment.