Regensburg 2007 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 1: Tutorial “Basics of Dielectric Solids”

DF 1.2: Tutorium

Sonntag, 25. März 2007, 15:00–16:00, H11

Experimental determination of linear and nonlinear material properties of dielectric solids — •Martin Diestelhorst — Martin-Luther-Universität Halle-Wittenberg, Institut für Physik, Friedemann-Bach-Platz 6, 06108 Halle

Dielectrics are interesting for many applications due to their elastic, electromechanic and dielectric properties. Often it is sufficient to know the linear coefficients like elastic compliance, piezoelectric coefficient and dielectric permittivity. A wide variety of experimental methods exist to determine these linear properties. Increasing the accuracy of measurements it becomes obvious that all of these properties are nonlinear. They depend on the amplitudes of external influences, e.g. the dielectric permittivity depends on the amplitude of the external electric field as well as on the external elastic stress. These higher order coefficients may be measured applying high electric fields or/and high elastic stresses to the samples under test. Additionally the progressive miniaturization often causes nonlinear behaviour, since e.g. even a small voltage applied to a dielectric film of few nanometers thickness corresponds to a high electric field strength along this direction. In practice nonlinear properties may be undesirable for many applications, but on the other hand there are special applications which could not be realized without these nonlinearities. Therefore it is necessary to characterize dielectric materials both concerning their linear and their nonlinear properties. The talk presents some experimental methods to allow for the determination of linear and nonlinear elastic, electromechanic and dielectric properties.