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dc.contributor.authorPontes, F. M.
dc.contributor.authorPontes, DSL
dc.contributor.authorLeite, E. R.
dc.contributor.authorLongo, Elson [UNESP]
dc.contributor.authorChiquito, A. J.
dc.contributor.authorMachado, MAC
dc.contributor.authorPizani, P. S.
dc.contributor.authorVarela, José Arana [UNESP]
dc.identifier.citationApplied Physics A-materials Science & Processing. New York: Springer-verlag, v. 78, n. 3, p. 349-354, 2004.
dc.description.abstractDielectric and Raman scattering experiments were performed on polycrystalline Pb1-xCaxTiO3 thin films (x=0.10, 0.20, 0.30, and 0.40) as a function of temperature. The results showed no shift in the dielectric constant (K) maxima, a broadening with frequency, and a linear dependence of the transition temperature on increasing Ca2+ content. on the other hand, a diffuse-type phase transition was observed upon transforming from the cubic paraelectric to the tetragonal ferroelectric phase in all thin films. The temperature dependence of Raman scattering spectra was investigated through the ferroelectric phase transition. The temperature dependence of the phonon frequencies was used to characterize the phase transitions. Raman modes persisted above the tetragonal to cubic phase transition temperature, although all optical modes should be Raman inactive. The origin of these modes was interpreted in terms of a breakdown of the local cubic symmetry due to chemical disorder. The lack of a well-defined transition temperature and the presence of broad bands in some temperature interval above the FE-PE phase transition temperature suggested a diffuse-type phase transition. This result corroborates the dielectric constant versus temperature data, which showed a broad ferroelectric phase transition in these thin films.en
dc.relation.ispartofApplied Physics A-materials Science & Processing
dc.sourceWeb of Science
dc.titleA Raman and dielectric study of a diffuse phase transition in (Pb1-xCax)TiO3 thin filmsen
dc.contributor.institutionUniversidade Federal de São Carlos (UFSCar)
dc.contributor.institutionUniversidade Estadual Paulista (UNESP)
dc.description.affiliationUniv Fed Sao Carlos, Dept Chem, CMDMC, LIEC, BR-13565905 Sao Carlos, SP, Brazil
dc.description.affiliationUniv Fed Sao Carlos, Dept Fis, BR-13565905 Sao Carlos, SP, Brazil
dc.description.affiliationUNESP, Inst Chem, Araraquara, SP, Brazil
dc.description.affiliationUnespUNESP, Inst Chem, Araraquara, SP, Brazil
dc.rights.accessRightsAcesso restrito
unesp.campusUniversidade Estadual Paulista (UNESP), Instituto de Química, Araraquarapt
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