Epitaxial growth and dielectric properties of (111) oriented BaTiO₃/SrTiO₃ superlattices by pulsed-laser deposition

Epitaxial BaTiO₃(111)/SrTiO₃(111) multilayered thin films have been investigated with various periods of stacking layer between 0.45/0.45 and 10/10 nm on Nb-doped SrTiO₃(111) substrates by a pulsed-laser deposition technique. Upon decreasing the period of each layer, the spacing of (111) plane (d₁₁₁) of the multilayered film increases, and the relative dielectric constant goes up to 594 which is twice as large as that of (111) oriented (Ba_0.5, Sr_0.5)TiO₃ solid-solution film. The expansion of d₁₁₁, which might be attributed to an in-plane pressure effect due to the large lattice strain in the heteroepitaxial interface, contributes to the enlargement of relative dielectric constant. Remanent polarization observed in polarization versus applied voltage hysteresis loop is no more than 2.7 μC/cm² with 2.0/2.0 nm period of layer. © 2000 American Institute of Physics.