X-ray diffraction patterns of film on substrate: (a) scan; the and peaks are marked by stars and down triangles, respectively. The peak labeled Au 111 is due to the gold contacts on the top of the film; (b) rocking curve for the BST 004 peak; (c) scan of the BST 301 peak.
Raman spectra of the films measured at in the parallel (solid lines) and crossed (dotted lines) polarization geometries. The stars mark the positions of the Raman lines related to the SRO buffer layer.
Raman spectra of the films with , 0.1, 0.2, and 0.5, measured in the perpendicular polarization geometry, as a function of temperature. The dashed-dotted arrows indicate the soft modes.
Temperature evolution of the Raman spectra of the films with and 0.5, measured in the parallel polarization geometry, as a function of temperature. The dashed-dotted arrows indicate the soft modes.
Temperature dependence of the and (circles), and (triangles) soft-mode frequencies for the films (solid symbols) and single crystals (open symbols). The hatched areas in (c) and (d) show the regions where the and soft modes in films are overdamped.
Raman spectra of the single crystal (top panel) and film of the same composition (bottom panel) at several temperatures below and above the ferroelectric phase transition. The stars in the spectra of the film mark the lines of the SRO buffer layer. The vertical dashed-dotted lines are guides to the eye.
Temperature dependence of the intensity of the hard phonon modes (circles) and (triangles) for the films with , 0.1, 0.2, and 0.5. The intensities are normalized to an intensity of the SRO phonon line. For the film, only the data are shown.
Top: Temperature dependence of the dielectric constant for the single crystal and film. Bottom: normalized soft-mode intensity as a function of temperature for these samples. The dashed-dotted lines indicate the determined from the Raman data.
Temperature dependence of the and soft-mode frequencies (circles) and damping (diamonds) for . Open symbols: single crystal, solid symbols: thin film. Horizontal bars show the temperature diapason where the soft mode is overdamped in films (black bar) and crystals (grey bar).
Ranges of the soft-mode overdamping as a function of Ba contents for the films (vertical error bars) and single crystals (shaded area). The symbols show the ferroelectric phase-transition temperatures for the single crystals (open circles) and films (triangles), as determined from the soft-mode behavior. The dotted lines represent the phase diagram for bulk BST (see Ref. 17).
(a) The inverse dielectric constant as a function of temperature for the film. (b) The temperature dependence of the square of the or soft-mode frequency for the same film; the dotted line shows the region where the soft mode is overdamped. (c) The or soft-mode damping. The vertical dashed-dotted lines are guides to the eye.
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