Orientation dependent leakage current behaviors and ferroelectric polarizations of off-axis sputtered BiFeO3 thin films

Epitaxial BiFeO3 thin films with (100), (110) and (111) orientations were grown on the SrRuO3-buffered SrTiO3 substrates by using an off-axis magnetron sputtering. Unlike the BiFeO3(110) and BiFeO3(111) thin films that exhibited a single rhombohedral phase structure, a dominant rhombohedral phase accompanying with a small amount of tetragonal phase was identified in the BiFeO3(100) thin film. In particular, the leakage currents and ferroelectric polarizations of sputtered BiFeO3 thin films were focused on and these films showed utterly different current density-electric field (J-E) behaviors whether in the positive or negative electric field. Among the three films, the ferroelectric polarization of the BiFeO3(100) thin film presented a good frequency stability and had the maximum remnant polarization of P-r similar to 78 mu C/cm(2) @ 10 kHz, which could be further demonstrated by pulsed polarizations of films. The distinct differences in electrical properties of orientation-engineered BiFeO3 thin films in present case can be attributed to their different crystallographic orientations and microstructures. (C) 2019 Elsevier B.V. All rights reserved.