Evaluation of discharge energy density of antiferroelectric ceramics for pulse capacitors

The energy in pulse capacitors need to discharge rapidly to obtain high peak power. However, the discharge energy density of antiferroelectric (AFE) dielectrics for pulse capacitors is traditionally evaluated by hysteresis loop (defined as quasi-static method). To verify whether the quasi-static method is suitable for pulse applications, AFE ceramics Pb_0.94La_0.04[(Zr_0.70Sn_0.30)_0.86Ti_0.14]O₃ were prepared, and their discharge energy density was calculated by hysteresis loop and pulse current (defined as dynamic method), respectively. A significant difference was found between these two kinds of results. Under 36 kV/cm, the discharge energy density calculated by 1 Hz hysteresis loop was 0.35 J/cm³ while that by pulse discharge current was only 0.18 J/cm³. It was found that the discharge energy density declined with increasing test frequency (0.1 Hz-100 Hz) and decreased further via dynamic hysteresis loop in microseconds scale. This declination can be explained by the viscous force during the motion of the domain wall. Thus, for pulse capacitors, it is more reasonable and practical to evaluate discharge energy density of AFE by pulse current than by quasi-static hysteresis loop.