Ferroelectric properties of epitaxial Bi2SiO5 thin films grown on SrTiO3 substrates with various orientations

Abstract

Ferroelectric properties of epitaxially grown Bi2SiO5 films were investigated. Bi2SiO5 films were deposited by pulsed laser deposition on SrTiO3 substrates with different orientations. Films with various orientations such as (100), (411), and (210)/(201) were successfully grown on SrTiO3 substrates with (100)-, (110)-, and (111)-orientations, respectively. Furthermore, Bi2SiO5 films deposited on (111)SrTiO3 substrates were highly (201)-oriented, indicating the selective growth of c-related facet due to the better lattice matching. Although Bi2SiO5 films do not contain perovskite blocks in its structure, film orientations of Bi2SiO5 were able to be controlled in a similar manner in the case of bismuth layered structure ferroelectrics with perovskite blocks. A (411)-oriented Bi2SiO5 film exhibited a clear ferroelectric feature and showed a saturation polarization of about 7.8 μC cm-2. Our findings show that epitaxial Bi2SiO5 thin films with a layered structure without perovskite blocks are a promising candidate for ferroelectric devices.