Growth mode and dielectric properties in laser MBE grown multilayer of SrTiO3 and YBa2Cu3Oy

We have prepared perovskite SrTiO3/YBa2Cu3Oy/LaAlO3 multilayer using laser molecular beam epitaxy technique. The evolution of growth mode from YBa2Cu3Oy followed by SrTiO3 was observed using in-situ reflective high-energy electron diffraction. The high-quality crystal structures of the grown films were also evidenced from X-ray diffraction analysis. The Raman scattering measurements were employed to study the lattice dynamic properties of SrTiO3 layer in the temperature range from 10 to 300 K. Strain and oxygen vacancies possibly contribute to the lowering of symmetry and the breaking of the central symmetry in SrTiO3. Temperature dependence of the dielectric constant and loss of thin films under different applied frequencies were evaluated.