Microstructure and electrical properties of epitaxial SrBi2Nb2O9 And SrBi2Ta2O9 films

Abstract SrBi2Nb2O9 (and in some cases SrBi2Ta2O9) epitaxial thin films were deposited on (001), (110), and (111) SrTiO3 substrates by pulsed laser deposition (PLD), both with and without epitaxial SrRuO3 bottom electrodes. Films grow epitaxially with the c-axis inclined by 0°, 45°, and 57° from the substrate surface normal, respectively. Greater tilts of the c-axis into the plane of the substrate surface provide a greater component of the polar axis (the a-axis of the orthorhombic unit cell) perpendicular to the substrate surface, leading to increased remanent polarization (P r) values. Portions of the same films used for electrical characterization were examined by transmission electron microscopy (TEM). Films have a single c-axis tilt angle and are fully crystalline with no observable second-phase inclusions. All films are observed to have a high density of out-of-phase boundaries (OPBs).