(100)-Oriented SrTiO3/BaTiO3 Artificial Superlattices Fabricated by Chemical Solution Deposition

Epitaxially grown SrTiO3(100)/BaTiO3(100) artificial superlattices with 7-nm-thick layers were synthesized on (100) platinum-coated (100) magnesium oxide substrates by a chemical solution deposition method. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) revealed cube-on-cube epitaxial growth. The Z-contrast HAADF-STEM image indicated that the SrTiO3 and BaTiO3 layers were fabricated without the intermixing of A-site atoms. The defects can only be observed in the boundary between the SrTiO3 and BaTiO3 layers. There was a mismatch of 3.0% between the in-plane lattice parameters of the SrTiO3 and BaTiO3 layers. This lattice mismatch induced the defects between the SrTiO3 and BaTiO3 layers. Inducing the defects between the layers relaxed the misfit strain.