Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DF: Dielektrische Festkörper
DF 2: Dielectric and Ferroelectric Thin Films and Nanostructures I
DF 2.6: Vortrag
Montag, 27. März 2006, 16:30–16:50, M{\"U}L Elch
Influence of layer defects in ferroelectric thin films — •Thomas Michael1, Julia Wesselinowa2, and Steffen Trimper1 — 1Fachbereich Physik, Martin-Luther-Universität, Friedemann-Bach-Platz, 06108 Halle — 2University of Sofia, Department of Physics, Blvd. J. Bouchier 5, 1164 Sofia, Bulgaria
Based on a modified Ising model in a transverse field we demonstrate that defect layers in ferroelectric thin films, originated by layers with impurities, vacancies or dislocations, are able to induce a strong increase or decrease of the polarization. The change is affected strongly by the variation of the exchange interaction within the defect layers. The applied Greens function methods enables us to calculate the polarization, the excitation energy and the critical temperature of the material with structural defects. Moreover, we find likewise the damping of the elementary excitation. The damping is increased due to interaction. The results are in qualitatively good agreement with experimental data for ferroelectric thin films. The model can be modified to discuss the polarization of ferroelectric nanoparticles. The nanoparticle is composed of layers with spherical and cylindrical geometry.
J. M. Wesselinowa, S.Trimper, and K.Zabrocki: Impact of layer defects in ferroelectric thin films, J.Phys.: Condens. Matter 17, 4687 (2005). J.M Wesselinowa,T.Michael,S.Trimper,and K.Zabrocki: Influence of layer defects on the damping in ferroelectric thin films, Phys. Lett.A in press. T.Michael, J.M.Wesselinowa, and S.Trimper: Ferroelectric nanoparticles (in preparation)