Regensburg 2010 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 7: Dielectric and ferroelectric thin films

DF 7.3: Vortrag

Dienstag, 23. März 2010, 14:40–15:00, H11

Nonlinear Frequency Response of Ferroelectric Thin Films — •Kay Barz, Martin Diestelhorst, and Horst Beige — Martin Luther-Universität Halle-Wittenberg

The dielectric properties of ferroelectric thin films are commonly studied by means of low-frequency or quasi-static methods (capacitance-voltage, current-voltage, hysteresis). We pursue a different approach by investigating the frequency response of a LCR series-resonant circuit containing a ferroelectric thin film as capacitance. The talk presents amplitude-frequency responses observed at different types of thin film samples (Metal/Oxid,Semiconductor (MOS), Metal/Ferroelectric/Metal (MFM), Metal/Ferroelectric/Semiconductor (MFS)).

The results on MFM structures show, how hysteresis and its transient alterations due to fatigue manifest in a shift of resonance frequency under increasing or decreasing driving amplitude. In the circuit configuration used to obtain the time series data, the MOS and MFS structures become electrostatically charged by the ac amplitude. In case of the MFS capacitor, in this charged state, a strange nonchaotic attractor can be observed. Thus, ferroelectric thin films and ferroelectric/semiconductor heterostructures provide experimental access to some interesting phenomena known from theory of nonlinear dynamics.