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-delta)-V response of a high voltage barium titanate ceramic disc capacitor with prescribed nonlinear CV response, as fabricated by the authors 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.