Dependence of dielectric and ferroelectric behaviors on growth orientation in epitaxial BaTiO3/SrTiO3 superlattices

Epitaxial BaTiO3/SrTiO3 dielectric superlattices have been prepared with molecular layer order accuracy by ArF pulsed laser deposition. Superlattices with various periods of stacking layer are constructed both on (00 1) and (1 1 1) Nb-doped SrTiO3 conductive substrates to elucidate orientation dependence of their dielectric behaviors. Results of reflection high-energy electron diffraction patterns combined with X-ray diffraction profiles show that the superlattices are completely epitaxial with the substrate. Superlattices with (001) orientation have large remanent polarization of 2Pr = 46muC/cm(2) in BaTiO3 (6.0 nm)/SrTiO3 (1.2 nm) imbalance thickness ratio. As for (111)-oriented superlattices, the relative dielectric constant goes up to 594 upon decreasing the period of the layer, which is twice as large as that of (111)-oriented (Ba-0.5,Sr-0.5)TiO3 solid-solution film. Typical remanent polarization 2Pr is 2.7 muC/cm(2). (C) 2002 Elsevier Science Ltd. All rights reserved.