Phase transitional studies of polycrystalline Pb0.4Sr0.6TiO3 films using Raman scattering

Pb0.4Sr0.6TiO3 films with submicron size grains have been prepared on Pt substrates by the metalorganic decomposition method. X-ray diffraction analysis reveals that the films are polycrystalline with, a perovskite crystal structure and negligible tetragonal splitting at room temperature. The room temperature Raman spectrum, however, shows all the characteristic phonon modes of a tetragonal ferroelectric phase. These modes lose their intensity with an increase in temperature but persist even up to 150degreesC. This is in agreement with the dielectric permittivity versus temperature data which show a broad peak-room temperature, and ferroelectric hysteresis persisting up to 140degreesC. Both Raman and dielectric data are interpreted as due to the presence of a distribution of phases in the film perhaps caused by a variation in Pb content along the film thickness and/or near grain boundary regions. (C) 2003 American Institute of Physics. [DOI: 10.1063/1.1534626].