METAL-OXIDE BILAYER RAMAN-SCATTERING IN SRTIO3 THIN-FILMS

We have used a metal-oxide bilayer Raman scattering technique to study lattice dynamics in SrTiO3 thin films. The SrTiO3 thin films were epi taxially grown on a conducting metal-oxide layer which reflects the ex citing laser beam so that it does not enter the LaAlO3 substrate. Rama n scattering from the SrTiO3 thin films was clearly observed, includin g the first-order Raman peaks forbidden by the cubic symmetry in singl e crystals. We suggest that strain exists in the films, which changes the crystal symmetry and will affect the dielectric properties of the SrTiO3 thin films. (C) 1998 American Institute of Physics. [S0003-6951 (98)02725-9].