DIELECTRIC-PROPERTIES OF (PB1-XXX)(ZR0.7TI0.3)O3 (X=CA, SR, BA) CERAMICS

The dielectric properties of (Pb1-xXx) (Zr0.7Ti0.3)O3 (X = Ca, Sr, Ba) ceramics (abbreviated PXZT) were investigated for applications to multilayer ceramic capacitors (MLCs) with dielectric layers thinner than 10 mum. The dissipation factors for MLCs with 5-mum-thick dielectric layers were estimated from those for 100-mum-thick disk specimens measured at an oscillation voltage of 20 V(rms). Those for PCZT and PSZT were less than 1.0% when the oscillation voltage was 20 V(rms), while those for conventional BaTiO3-based dielectric ceramics were greater than 2.5% at 20 V(rms). According to polarization-electric field hysteresis measurements, PCZT and PSZT revealed linear and double hysteresis loops, respectively, while PBZT and BaTiO3 indicated typical ferroelectric hysteresis loops. The differences in the dissipation factors for the dielectric compositions are attributed to hysteresis in the polarization-electric field loops. These results suggest that PCZT and PSZT are promising dielectric ceramics for MLCs with dielectric layers thinner than 10 mum.