Regensburg 2013 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 8: Application of dielectric solids

DF 8.1: Vortrag

Montag, 11. März 2013, 16:50–17:10, H11

Influence of dielectric nonlinearities on the storable energy of BaTiO₃-capacitors — •Tino Band¹, Sebastian Lemm¹, Mandy Zenkner², Martin Diestelhorst¹, Albrecht Rost³, Horst Beige¹, and Stefan Ebbinghaus² — ¹Institute of Physics, Martin-Luther-University Halle-Wittenberg, D-06099 Halle, Germany — ²Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, D-06099 Halle, Germany — ³University of Applied Sciences Merseburg, 06217 Merseburg, Germany

The concept of energy storage in a capacitor is of great interest in connection with the energy production based on wind energy or solar energy. According to the commonly used linear relation for the energy density w_el=1 /2 ε₀ε E² of an electric field a capacitor may store the total amount of electric energy W_el= 1 /2 C U². The aim is to find dielectrics with high permittivities ε and high dielectric strength to store large quantities of electric energy without increasing the volume of the capacitor too much. At a first glance ferroelectrics are good candidates because of their relatively high values of small-signal dielectric permittivities ε. But it is well known that they are nonlinear dielectrics. We discuss the influence of dielectric nonlinearities on the amount of storable energy. As will be shown the nonlinear dielectric properties reduce the storable energy in ferroelectric capacitors compared to the estimations of the linear model. We present results of detailed hysteresis measurements and charge-discharge measurements on ceramic BaTiO₃-samples to demonstrate the limitations of the linear model.