Growth and structural characterization of epitaxial Ba0.6Sr0.4TiO3 films deposited on REScO3(1 1 0) (RE=Dy, Gd) substrates using pulsed laser deposition

Abstract Ba 0.6 Sr 0.4 TiO 3 films were deposited by pulsed laser deposition on orthorhombic REScO 3 (1 1 0) (RE=Dy, Gd) single-crystal substrates. Films were investigated for their growth mode, crystalline quality, and strain states. Substrates were treated prior to growth to produce atomically flat surfaces having wide terraces (≈200 nm) and clear unit-cell-high steps. Atomic force microscopy and reflection high-energy electron diffraction indicated that the films grew epitaxially in a two-dimensional (2D) layer-by-layer mode. X-ray diffraction showed that all films (200 nm thick and less) were coherently/orthorhombically strained to the substrate according to the epitaxial relationship: (0 0 1) film ∥(1 1 0) substrate ; [1 0 0] film ∥[0 0 1] substrate (and [0 1 0] film ∥[1 1¯ 0] substrate ). (0 0 2) rocking curves were 17 and 20 arcsec wide for films grown on RE=Dy and Gd, respectively.These films have rocking curve widths and dislocation densities that are several orders of magnitude lower than a film grown on SrTiO 3 (0 0 1).