Figure 3.

Characterization data for thin films of ScFeO₃ grown on SrTiO₃ (100) substrates. The epitaxial relationship of the film to substrate was [2–21]_SFO (cor)||[001]_STO and (012)_SFO (cor)|| (010)_STO. (a) out-of-plane X-ray diffraction scan indexed to the perovskite pseudocubic cell (gray italic indices indicate a reflection from the substrate) with lattice vector relations of [0 0 1]_per ∥ [2 −2 1]_corand (0 1 0)_per ∥(0 1 2)_cor. (b) Reciprocal space map about the (0–33) reflection of the substrate showing coherent alignment of Fe₂O₃ (FO) with ScFeO₃ (0 3 −12)_SFO (cor)∥ (1 3 10)_FO The ScFeO₃ peak is indexed to the perovskite pseudocubic cell. The breadth of the film peak is assigned to strain gradients moving away from the substrate and the domain structure within the film. (c) High resolution HAADF-STEM image of the substrate film interface, the white arrow indicates a boundary between two twin domains. This twinning is due to the rhombohedral distortion having four possible orientations when growing on the cubic SrTiO₃ surface. (d) Schematic indicating the registry of the ScFeO₃ thin films (top) to the SrTiO₃ substrate (bottom). The perovskite pseudocubic cell is indicated and its relationship to the corundum cell. For clarity, the Sc and Fe site are shown disordered with the Sc octahedra removed. Perovskite cell highlighted with respect to the substrate (e) and orientation of the rhombohedral cell with respect to the perovskite cell. In the Figure the out-of-plane lattice parameter is that determined experimentally and the in-plane is set equal to SrTiO₃ with γ = 90° rather than the bulk rhombohedral angle. The experimentally determined γ = 89.2°.