Aspects of modeling of high voltage ferroelectric nonlinear ceramic capacitors

Experimental and theoretical studies are reported on the room temperature capacitance-voltage (CV) and (tan δ)-V response of a high-voltage barium titanate ceramic disc capacitor with prescribed nonlinear CV response, as fabricated for an intended power electronics application. The CV response was modeled in terms of a voltage-dependent series equivalent circuit incorporating grain-boundary junction capacitances and grain ferroelectric capacitances. A modified Langevin function was used to relate intergrain ferroelectric polarization, which yielded good agreement between theory and experiment for a 3-to-1 capacitance variation over the DC bias range up to 1000 V