Preparation of epitaxial SrBi2Nb2O9 and SrBi2Ta2O9 thin films by the coating-pyrolysis process

Epitaxial and polycrystalline thin films of bismuth layer-structured ferroe lectrics, SrBi2Nb2O9 (SBN) and SrBi2Ta2O9 (SBT), were prepared on single-cr ystal SrTiO3(001) and polycrystalline yttria-stabilized zirconia substrates , respectively, by the coating-pyrolysis process. The epitaxial relationshi p of the films and substrates was SBN, SBT (001)//SrTiO3(001) and SBN, SET [100]//SrTiO3[100],[010], where pseudotetragonal indices were adopted for S BN and SET. The lattices of the epitaxial films were found to be slightly s trained owing to stress from the substrate. Atomic force microscopy observa tions showed that the epitaxial films as well as polycrystalline films cons isted of round-shaped, islandlike grains of submicrometer size.