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DF: Dielektrische Festkörper
DF 5: Nichtlineare Eigenschaften, Störstellen
DF 5.5: Talk
Wednesday, March 24, 1999, 16:10–16:30, R2
Molecular field theory and nonlinear dielectric susceptibility of SrTiO3 — •W. Kleemann1, S.A. Prosandeyev2, and J. Dec3 — 1Angewandte Physik, Gerhard-Mercator-Universität Duisburg, 47048 Duisburg — 2Rostov State University — 3Silesian University Katowice
Formally equivalent expressions emerge for the free energy of quantum
paraelectrics like SrTiO3 within the framework of both the
Salje-Wruck-Thomas and the transverse Ising model. In agreement with
experimental results scaling relations involving quasicritical
exponents are deduced for the dielectric susceptibility
in dependence on the quantum temperature TQ=Tscoth(Ts/T) and
on
the external electric field, E. The field dependence of the
susceptibility
evidences that it is primarily due to polar clusters, which start to
grow
on a nanoscale below about 40K.