Simulation of the dielectric response of piezoelectric ceramics

Abstract

We have analyzed the complex permittivity of a porous (10 volume % of pores) sodium-lithium niobate ceramic with the results of computer simulation. The calculation was based on the Cole–Cole formula, which took into account the presence of various mechanisms of relaxation processes in the low-frequency (linear dispersion) and mid-frequency regions, an additional term from the Debye formula was added to take into account the mixed polarization, and a term taking into account the damping factor was added for resonant-type polarization. The simulation was carried out with and without the conductivity taken into account. To take into account the contribution of conductivity to the dynamic dielectric response, the expression σ* = (ε″ + iε′)ε0ω was used. It is shown that the linear part of the frequency dependence in the range from 50 Hz to 1 MHz is equally well described both with and without conductivity. At the same time, the behavior of the dielectric response of piezoelectric ceramics in the high-frequency region, where resonance effects are observed, and the low-frequency region, where volume-charge polarization predominates, is much better described taking into account the contribution of conductivity to the dielectric response of the system.

Keywords

• piezoelectric ceramics
• complex permittivity
• complex conductivity
• dielectric spectroscopy