Microstructure and ferroelectric properties of epitaxial BaTiO3/SrRuO3/SrTiO3 (001) films grown by pulsed laser deposition under high oxygen pressure

► C-axis-oriented BaTiO3 films were prepared under high oxygen pressure of 30 Pa. ► BaTiO3 films with columnar structure were obtained. ► The dielectric constant showed a peak at the Curie temperature around 356 K. ► Saturated hysteresis loops are observed with a remnant polarization of 7.3 μC/cm2.