Epitaxially strained BaTiO3 thin films on LaAlO3 substrates with La0.5Sr0.5MnO3 electrodes: Enhanced ferroelectric property and domain structure

BaTiO3 (BTO) thin films were epitaxially deposited on LaAlO3(LAO) substrates with epitaxial La0.5Sr0.5MnO3(LSMO) electrodes by pulsed laser deposition. We confirmed that the epitaxial BTO thin films on LSMO/LAO substrates remarkably showed the increased remnant polarization in comparison with the epitaxial BTO thin films on Pt/MgO substrates. It was inferred that the enhanced ferroelectric polarization in the epitaxial BTO thin films on LSMO/LAO substrates arose from the increased tetragonality with the c/a ratio of 1.04. Piezoresponse force microscopy study revealed that the epitaxial BTO thin film on LSMO/LAO substrate possessed higher domain wall energy than that of the PbTiO3 thin films, which implies fine domain structure of the epitaxial BTO thin films on LSMO/LAO substrates.