By data analysis the ordinary differential equation for the description of an experimental electric resonance circuit with nonlinear capacitor is derived. Triglycine sulfate (TGS) was used as nonlinear dielectric material. This is the most thoroughly investigated ferroelectric with a second order phase transition. Its static dielectric small signal behavior is well described in the framework of the Landau theory, yielding a Duffing-type ordinary differential equation as a model equation of the circuit. Data analysis allows us to check carefully the validity of this model and to determine required corrections of this simplified equation. (c) 1998 American Institute of Physics.

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Composite thin films of surface functionalized CaCu3Ti4O12 prepared by spin-coating show a fivefold increase of the relative permittivity compared to the pure P(VDF-HFP) polymer.

BaTiO3–P(VDF-HFP) composite films without surface functionalization show a tenfold increase of the relative permittivity compared to the pure polymer.

We investigate the behavior of an experimental electric resonance circuit with a nonlinear capacitor. Triglycine sulfate (TGS) was used as nonlinear dielectric material. This is the most thoroughly investigated ferroelectric with a second-order phase transition. Its static dielectric small signal behavior is well described in the framework of the Landau theory of phase transitions. The dynamic behavior however is strongly related to relaxation phenomena due to switching of domains. Here the theoretical situation is still unclear. By mere data analysis we construct an ordinary differential equation which describes the dynamical behavior of the circuit, and which is simple in the sense of Ockham's razor. The structure of this equation is closely related to the dynamical properties of the ferroelectric. We are therefore able to gain some insights into the dynamical behavior of ferroelectrics, which may give some hints for a more exhaustive analysis of nonequilibrium properties of ferroelectrics.