Structural properties and polarization switching of epitaxial Bi2FeCrO6 thin films grown on La2/3Sr1/3MnO3/SrTiO3 (111) substrates

Abstract

• High quality ferroelectric Bi 2 FeCrO 6 films were prepared by pulsed laser deposition. • The films exhibit a grained structure with an in-plane grain size of about 200 nm. • The as-grown film show a preferential upward polarization direction. • An asymmetric polarization switching is observed due to interface effects. • A mutual influence between polarization and interface bias field is evidenced. Ferroelectric Bi 2 FeCrO 6 (BFCO) double perovskite thin films were grown by pulsed laser deposition on SrTiO 3 (111) covered with a 20 nm thick La 2/3 Sr 1/3 MnO 3 buffer layer. X-ray diffraction measurements performed in θ-2θ and φ scans modes reveal an epitaxial growth of the BFCO with a compressive in-plane strained structure and no spurious phases. The presence of superstructure diffraction peaks indicates an Fe-Cr cationic ordering along the growth axis. Local measurements realized by piezo-response force microscopy show an asymmetric polarization switching with respect to the external bias voltage suggesting the presence of a bias field. This agrees with a preferential ferroelectric polarization observed upon local poling of the BFCO film in opposite directions. The findings can be of importance for understanding the relationship between the atomic structure and polarization dynamics in ferroelectric thin-films.