Difference Raman spectra of PbTiO[sub 3] thin films grown by metalorganic chemical vapor deposition

The technique of Raman scattering has been used to investigate the properties of ferroelectric PbTiO[sub 3] thin films grown on both single-crystal KTaO[sub 3] and fused quartz substrates by means of metalorganic chemical vapor deposition. The difference Raman'' technique was employed in which substrate contributions were subtracted in order to obtain Raman spectra for the PbTiO[sub 3] films. A comparison of the Raman spectra taken at 300 and 80 K for PbTiO[sub 3] and KTaO[sub 3] reveals two different types of temperature behavior and these effects are accounted for by the soft-mode theory.