We report a study of residual stress in PbTiO 3 (PT) thin films prepared on Si substrates by a polymeric chemical method. The E(1TO) frequency was used to evaluate the residual stress through an empirical equation available for bulk PT. We find that the residual stress in PT films increases as the film thickness decreases and conclude that it originates essentially from the contributions of extrinsic and intrinsic factors. Polarized Raman experiments showed that the PT films prepared by a polymeric chemical method are somewhat a-domain (polar axis c parallel to the substrate) oriented.

We report Raman scattering and x-ray diffraction studies of polycrystalline CaCu 3 Ti 4 O 12 (CCTO) under high pressures. The pressure dependence of several Raman modes was investigated. No anomalies have been observed on the phonon spectra thereby indicating that the T h ͑Im 3͒ structure remains stable up to the maximum pressure ͑5.3 GPa͒ we reached in this experiment. The pressure coefficients for the observed Raman modes were determined. This set of parameters was used for evaluating the stress developed in CCTO thin films. The high-pressure x-ray studies were extended up to 46 GPa and the data confirmed that the T h structure remains stable up to this pressure. The pressure-volume data are well described by the Birch's equation of state. The experimental value of the zero pressure bulk modulus is B 0 = 212± 2 GPa. Grüneisen parameters of CCTO were also determined.

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