Regensburg 2002 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DF: Dielektrische Festkörper
DF 4: Keramiken, Gradientenwerkstoffe und Relaxoren
DF 4.4: Vortrag
Dienstag, 12. März 2002, 15:50–16:10, 11
Dielectric response, second-harmonic generation and random-field induced domain wall response of SrTi18O3 — •Lei Zhang1, Wolfgang Kleemann1, Jan Dec1, Peer Lehnen1, Ruiping Wang2, and Mitsuru Itoh2 — 1Laboratorium für Angewandte Physik, Gerhard-Mercator-Universität Duisburg, 47048 Duisburg — 2Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
The dielectric permittivity є’-iє” and optical second-harmonic generation (SHG) of SrTi18O3 are studied under a dc electric field E as a function of the temperature, T. In є’ vs. T, a double-peak is found when 0 < E < 30kV/m. While the peak at high-T is attributed to the smeared ferroelectric phase transition, the low-T one is induced by domain wall motion. Optical SHG shows that the SrTi18O3 develops polar regions on cooling towards the phase transition at Tc ≈ 24K. The transverse Ising model including an external homogeneous and quenched random-fields is successfully used to describe both the smeared phase transition and the domain wall response in the low-T domain state.