We report a UV-Raman study of folded acoustic vibrations in epitaxial ferroelectric BaTiO3/SrTiO3 superlattices. The folded acoustic doublets show an anomalous temperature dependence disappearing above the ferroelectric transition, which is tuned by varying the thickness of the BaTiO3 and SrTiO3 layers. A mechanism involving the acoustic phonon modulation of the spatially periodic ferroelectric polarization explains the observed temperature dependence. These results demonstrate the strong coupling between sound, charge, and light in these multifunctional nanoscale ferroelectrics.
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http://dx.doi.org/10.1103/PhysRevLett.101.197402 | DOI Listing |
Beilstein J Nanotechnol
August 2018
Institute of Physics, The Czech Academy of Sciences, 182 21 Prague, Czech Republic.
The phase-field simulations of ferroelectric Bloch domain walls in BaTiO-SrTiO crystalline superlattices performed in this study suggest that a paraelectric layer with a thickness comparable to the thickness of the domain wall itself can act as an efficient pinning layer. At the same time, such a layer facilitates the possibility to switch domain wall helicity by an external electric field or even to completely change the characteristic structure of a ferroelectric Bloch wall passing through it. Thus, ferroelectric Bloch domain walls are shown to be ideal nanoscale objects with switchable properties.
View Article and Find Full Text PDFNat Commun
December 2015
Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA.
In epitaxially strained ferroelectric thin films and superlattices, the ferroelectric transition temperature can lie above the growth temperature. Ferroelectric polarization and domains should then evolve during the growth of a sample, and electrostatic boundary conditions may play an important role. In this work, ferroelectric domains, surface termination, average lattice parameter and bilayer thickness are simultaneously monitored using in situ synchrotron X-ray diffraction during the growth of BaTiO3/SrTiO3 superlattices on SrTiO3 substrates by off-axis radio frequency magnetron sputtering.
View Article and Find Full Text PDFJ Phys Condens Matter
April 2013
Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200062, People's Republic of China.
We report a systematic theoretical study on the ferroelectric behavior of ultrathin three-component ferroelectric films, e.g., CaTiO3-BaTiO3-SrTiO3, sandwiched between electrodes.
View Article and Find Full Text PDFPhys Rev Lett
November 2008
Instituto Balseiro & Centro Atómico Bariloche, C.N.E.A., R8402AGP Bariloche, Río Negro, Argentina.
We report a UV-Raman study of folded acoustic vibrations in epitaxial ferroelectric BaTiO3/SrTiO3 superlattices. The folded acoustic doublets show an anomalous temperature dependence disappearing above the ferroelectric transition, which is tuned by varying the thickness of the BaTiO3 and SrTiO3 layers. A mechanism involving the acoustic phonon modulation of the spatially periodic ferroelectric polarization explains the observed temperature dependence.
View Article and Find Full Text PDFOpt Express
May 2008
VTT Technical Research Centre of Finland, Kaitovayla 1, Fin-90571 Oulu, Finland.
Artificial BaTiO(3)-SrTiO(3) superlattices with stacking periodicity varying between 27 and 1670 A in separate films were grown on MgO substrates by pulsed laser deposition. Both the static and active optical properties were found to be sensitive on the stacking periodicity. Birefringence decreased with increasing individual layer thickness due to relaxation of the interface originated stress.
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