Abstract
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 language | English |
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Pages (from-to) | 326-330 |
Number of pages | 5 |
Journal | Journal of Raman Spectroscopy |
Volume | 43 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Feb 2012 |
Keywords
- Brillouin scattering
- diffuse phase transition
- polar nanoregion
- Raman scattering
ASJC Scopus subject areas
- Materials Science(all)
- Spectroscopy