Microstructure and electrical properties of epitaxial SrBi(sub 2)Nb(sub 2)O(sub9) and SrBi(sub 2)Ta(sub 2)O(sub 9) films

摘要

SrBi2(sub)Nb2(sub)O9(sub) (and in some cases SrBizTa2(sub)09(sub)) epitaxial thinfilms were deposited on (001),(110), and (111) SrTiO3(sub) substrates by pulsed laser deposition (PLD), both with and without epitaxial SrRuO3(sub) bottom electrodes. Films grow epitaxially with the c-axis inclined by 0 degr.,45 degr., and 57 degr. 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 (Pr (sub)) 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 filly crystalline with no observable second-phase inclusions. All films are observed to have a high density of out-of-phase boundaries (OPBs).