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DF: Fachverband Dielektrische Festkörper

DF 13: Applications of dielectric solids

DF 13.1: Vortrag

Mittwoch, 2. April 2014, 11:50–12:10, GER 37

Why should one account for dielectric nonlinearities — •Martin Diestelhorst — Martin-Luther-Universität Halle, Wittenberg, Institut für Physik, Von-Danckelmann-Platz 3, 06120 Halle, diestelhorst@physik.uni-halle.de

Many applications of dielectrics assume the materials to be linear. That is often legitimated by confining the choice of parameters to ranges, for which that assumption is valid. However for some applications it is necessary to apply such high external fields, that one has to take into account deviations from the linear behaviour. On the one hand these nonlinearities may be harmful for some applications. Otherwise there could arise applications that may be realized only utilizing the nonlinear properties. Especially when using ferroelectric materials one has to be aware of the dielectric nonlinearities. We discuss implications for both cases of applications. As an example for the first case we consider the process of energy storage on a capacitor with ferroelectric material as dielectric, where the stored energy falls short of the amount extrapolated from small signal permittivities to high electric fields assuming linear behaviour. The second example is concerned with a parametric amplifier in a nonlinear series circuit with ferroelectric capacitor. The described effect is observable near period doubling bifurcations which may not be observed in linear circuits.