Equivalent Circuit Modelling of the Time-Dependent Poling Behaviour of Ferroelectric Multilayer Structures

Monolithic ceramics with a gradient of the piezoelectric activity along the thickness are suitable for ultrasonic applications and bending devices. In order to impress piezoelectric properties, a poling process is necessary. Ferroelectric multilayer structures can be regarded as model systems for functionally graded materials. Moreover, the switching process in ferroelectric capacitors is interesting due to their application in nonvolatile memories.

The time-dependent poling behaviour of ferroelectric multilayer systems was described by using an equivalent circuit analysis. For that purpose, each layer is modelled as a parallel circuit of a capacitor with dielectric and a resistor. They are connected in serial. In consideration of elementary electric laws, a system of time-dependent ordinary differential equations for the electric field strengths in each layer can be found. The hysteresis loops are modelled by using the Preisach model. This approach was applied to a model structure consisting of two layers of tin-doped BaTiO ₃ .

Keywords:

• Ferroelectric properties
• capacitors
• composites
• BaTiO₃
• Preisach model

AIP:

• 77.80.Dj
• 77.80.Fm
• 77.84.Dy

Acknowledgments

This work was supported by a scholarship of the state Sachsen-Anhalt, Germany, and the Deutsche Forschungsgemeinschaft.