Nanoscale domains in strained epitaxial BiFeO3 thin Films on LaSrAlO4 substrate

摘要

BiFeO3 thin films with various thicknesses were grown epitaxially on u0002001u0003 LaSrAlO4 single crystalnsubstrates using pulsed laser deposition. High resolution x-ray diffraction measurements revealednthat a tetragonal-like phase with c-lattice constant u00044.65 Å is stabilized by a large misfit strain.nBesides, a rhombohedral-like phase with c-lattice constant u00043.99 Å was also detected at filmnthickness of u000450 nm and above to relieve large misfit strains. In-plane piezoelectric forcenmicroscopy studies showed clear signals and self-assembled nanoscale stripe domain structure fornthe tetragonal-like regions. These findings suggest a complex picture of nanoscale domain patternsnin BiFeO3 thin films subjected to large compressive strains.