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Full-Text Articles in Physics
Ferroelectricity In Non-Stoichiometric Srtio3 Films Studied By Ultraviolet Raman Spectroscopy, Dmitri A. Tenne, A. K. Farrar
Ferroelectricity In Non-Stoichiometric Srtio3 Films Studied By Ultraviolet Raman Spectroscopy, Dmitri A. Tenne, A. K. Farrar
Physics Faculty Publications and Presentations
Homoepitaxial Sr1+xTiO3+δ films with -0.2 ≤ x ≤ 0.25 grown by reactive molecular-beam epitaxy on SrTiO3 (001) substrates have been studied by ultraviolet Raman spectroscopy. Non-stoichiometry for strontium- deficient compositions leads to the appearance of strong first-order Raman scattering at low temperatures, which decreases with increasing temperature and disappears at about 350 K. This indicates the appearance of a spontaneous polarization with a paraelectric-to-ferroelectric transition temperature above room temperature. Strontium-rich samples also show a strong first-order Raman signal, but the peaks are significantly broader and exhibit a less pronounced temperature dependence, indicating a stronger contribution …
Ferroelectric Phase Transitions In Three-Component Short-Period Superlattices Studied By Ultraviolet Raman Spectroscopy, Dmitri Tenne, H. N. Lee, R. S. Katiyar, X. X. Xi
Ferroelectric Phase Transitions In Three-Component Short-Period Superlattices Studied By Ultraviolet Raman Spectroscopy, Dmitri Tenne, H. N. Lee, R. S. Katiyar, X. X. Xi
Physics Faculty Publications and Presentations
Vibrational spectra of three-component BaTiO3SrTiO3CaTiO3 short-period superlattices grown by pulsed laser deposition with atomic-layer control have been investigated by ultraviolet Raman spectroscopy. Monitoring the intensity of the first-order phonon peaks in Raman spectra as a function of temperature allowed determination of the ferroelectric phase transition temperature, Tc. Raman spectra indicate that all superlattices remain in the tetragonal ferroelectric phase with out-of-plane polarization in the entire temperature range below Tc. The dependence of Tc on the relative thicknesses of ferroelectric (BaTiO3) to non-ferroelectric materials (SrTiO3 and CaTiO3 …
Interfacial Coherency And Ferroelectricity Of Batio3/Srtio3 Superlattice Films, Y. L. Li, S. Y. Hu, Dmitri Tenne, A. Soukiassian, D. G. Schlom, X. X. Xi, K. J. Choi
Interfacial Coherency And Ferroelectricity Of Batio3/Srtio3 Superlattice Films, Y. L. Li, S. Y. Hu, Dmitri Tenne, A. Soukiassian, D. G. Schlom, X. X. Xi, K. J. Choi
Physics Faculty Publications and Presentations
We studied the phase transitions, domain morphologies, and polarizations in BaTiO3/SrTiO3 superlattices grown on SrTiO3 substrates. Using the phase field approach, we discovered the remarkable influence of film/substrate interfacial coherency on the ferroelectricity of the SrTiO3 layers within a superlattice: it is an orthorhombic ferroelectric for an incoherent interface while it exhibits only induced polarization by the adjacent BaTiO3 layers for a coherent interface. We presented the domain morphologies within individual BaTiO3 and SrTiO3 layers which have different ferroelectric symmetries. The results are compared to ultraviolet Raman spectroscopy and variable temperature x-ray …