Inelastic light scattering studies of diffuse phase transition in ferroelectric Sr1.9Ca0.1NaNb5O15thin films

W. C. Liu, W. Zhou, R. Sooryakumar, Chee Leung Mak

Research output: Journal article publicationJournal articleAcademic researchpeer-review

11 Citations (Scopus)


The dynamic behavior of highly oriented ferroelectric Sr1.9Ca0.1NaNb5O15thin films has been investigated by Brillouin light scattering over a wide temperature range between 25 and 450°C. The temperature variations of the full-width at half-maximum (FWHM) of the central peak (CP) are found to exhibit marked changes around the Curie temperature (Tc= 246°C). The CP reveals a relaxational mode behavior, which is attributed to thermally activated fast relaxation of polar nanoregions (PNRs). The width of the CP decreases steadily upon cooling from ∼400°C to Tcand shows little subsequent change within the ferroelectric state, indicating an increase of the number of PNRs and a slowing down of their dynamics. By using a modified superparaelectric model, the activation energy (H0) of the relaxation processes and the Burns temperature (TB) are determined to be 2939 and 385°C, respectively. The evidence for this diffuse phase transition provided by Brillouin scattering is in agreement with results obtained from the temperature-dependent dielectric permittivity, refractive index, and Raman spectra.
Original languageEnglish
Pages (from-to)326-330
Number of pages5
JournalJournal of Raman Spectroscopy
Issue number2
Publication statusPublished - 1 Feb 2012


  • Brillouin scattering
  • diffuse phase transition
  • polar nanoregion
  • Raman scattering

ASJC Scopus subject areas

  • Materials Science(all)
  • Spectroscopy

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