Physics Commons^™

Ferroelectricity In Non-Stoichiometric Srtio3 Films Studied By Ultraviolet Raman Spectroscopy, Dmitri A. Tenne, A. K. Farrar

Physics Faculty Publications and Presentations

Homoepitaxial Sr_1+xTiO_3+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 …