Structure and electrical properties of cc-axis epitaxial Srm−3Bi4TimO3m+3(m=5 and 6) thin films

CC-axis epitaxial Srm−3Bi4TimO3m+3 (SBTimm, m=5m=5 and 6) thin films were fabricated on conductive LaNiO3 (LNO) coated LaAlO3 (LAO) substrates by pulsed laser deposition. The structure was characterized by x-ray diffraction (including θ−2θθ−2θ, rocking curve, and ϕϕ scans) and atomic force microscopy. The epitaxial relationship was established (001)SBTimm//(001)LNO//(001)LAO, [100]SBTimm//[110]LNO//[110]LAO when orthorhombic structure indexing was used for SBTimm. It is revealed that the films with odd mm have a ferroelectric hysteresis loops whereas those with even mm have collinear polarization-electric field curves. The microstructure background responsible for the observations was discussed. Our results provide further evidence that the cc-axis polarization of Bi-layered oxides depends on the parity of mm.