Microstructure and electrical properties of epitaxial SrBi2Nb2O9 and SrBi2Ta2O9 films

SrBi2Nb2O9 (and in some cases SrBi(2)TazO(9)) epitaxial thin films were dep osited on (001). (110), and (111) SrTiO3 substrates by pulsed laser deposit ion (PLD), both with and without epitaxial SrRuO3 bottom electrodes. Films grow epitaxially with the c-axis inclined by Oo, 45 degrees, and 57 degrees from the substrate surface normal, respectively. Greater tilts of the c-ax is into the plane of the substrate surface provide a greater component of t he polar axis (the a-axis of the orthorhombic unit cell)perpendicular to th e substrate surface, leading to increased remanent polarization (P-r) value s. Portions of the same films used for electrical characterization were exa mined by transmission electron microscopy (TEM). Films have a single c-axis tilt angle and are fully crystalline with no observable second-phase inclu sions. All films are observed to have a high density of out-of-phase bounda ries (OPBs).