High capacity dielectric/ PbZr_(0.4)Ti_(0.6)O_3/dielectric stacks for charge storage

Based on Landau-Devonshire free energy theory,a thermodynamic model was built for dielectric/ PbZr0.4Ti0.6O3/dielectric sandwich structures.The relationship of critical fraction and dielectric er was investigated,then to gain charge storage capacity.The results show that high capacitance densities can be achieved when the total dielectric thickness reaches a critical fraction.The critical fraction increase with the increase of dielectric constant of dielectric layer,meanwhile,the less average dielectric response is,the larger the polarizability of dielectric layer induced by inner electric field is.As far as SiO2/ PbZr0.4Ti0.6O3/SiO2 be concerned,the critical fraction is about 0.37%,the average dielectric response is about –2.42×104.