Regensburg 2007 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 10: Dielectric and Ferroelectric Thin Films and Nanostructures III

DF 10.5: Talk

Thursday, March 29, 2007, 15:50–16:10, H48

Ferroelectric like hysteresis and piezoelectricity in open porous polymers: theoretical predictions and experimental observations — •Sergej Zhukov and Heinz von Seggern — Electronic Materials Division, Institute of Materials Science, Darmstadt University of Technology, Petersenstrasse 23, 64287 Darmstadt

The open porous polymers form a new attractive class of piezoelectric materials. Up to now it has been demonstrated that the porous film after proper charging and polarizing is responsible for the high piezoelectric response if confined between two electrically blocking layers. Such sandwich-structures reveal outstandingly large quasi-static piezoelectric coefficients of up to 1000pC/N. Here a theoretical model is proposed for a 3-layer sandwich which quantitatively explains obtainable polarization and its hysteresis behaviour at different poling voltages. It is observed that such sandwich structures exhibit a certain poling limit above which the induced polarization becomes unstable due to back-switching. This phenomenon limits the obtainable remanent polarization and hence the piezoactivity of sandwich structures. The variation of the maximum remanent polarization for different polymer film thicknesses will also be reported.

The work is supported by Arbeitsgemeinschaft industrieller Forschungsvereinigungen (AiF) *Otto von Guericke* e.V.