Microstructure and properties of epitaxial La0.7Sr0.3MnO3/BaTiO3 bilayer film grown by pulsed laser deposition

La0.7Sr0.3MnO3/BaTiO3 bilayer films were grown on SrTiO3 (001) substrates buffered with SrRuO3 films as the bottom electrodes by pulsed laser deposition. The quality of the La0.7Sr0.3MnO3/BaTiO3/SrRuO3/SrTiO3 films was analyzed by means of transmission electron microscopy and atomic force microscopy. It is found that each layer grows epitaxially on its bottom layer. La0.7Sr0.3MnO3/BaTiO3 bilayer films exhibit typical ferroelectric hysteresis loops for BaTiO3 films with the remnant polarization of 16.2 μC/cm2 at driven field of 278 kV/cm and ferromagnetic hysteresis loops for La0.7Sr0.3MnO3 film with the coercive field of about 4 kA/m and the saturation magnetization of 205 kA/m at 295 K. The effect of ferroelectric BaTiO3 layer poling on the resistivity of ferromagnetic La0.7Sr0.3MnO3 layer was also investigated.