Ferroelectric properties of (Ba[sub 0.5]Sr[sub 0.5])TiO₃/Pb(Zr[sub 0.52]Ti[sub 0.48])O₃/(Ba[sub 0.5]Sr[sub 0.5])TiO₃ thin films with platinum electrodes

Abstract

Multilayered Pt/(Ba[sub 0.5]Sr[sub 0.5])TiO₃ /Pb(Zr[sub 0.52]Ti[sub 0.48])O₃/(Ba[sub 0.5]Sr[sub 0.5])TiO₃/Pt (BST/PZT/BST) thin films with different thicknesses of the BST layers were prepared by the pulsed-laser deposition method. The existence of a BST layer between the PZT and Pt electrode can greatly improve the fatigue properties of the PZT film. However, the heterostructure with thicker BST layers exhibits lower remnant polarization because of a lower electric field applied on the PZT layer. So, the thickness of BST layers should be decreased to decrease the working voltage of the multilayered film. A heterostructure with very thin BST layers (thickness ~7.5 nm) has good ferroelectric properties, such as high remnant polarization and rare fatigue resistance after 10[sup 10] switching cycles. A possible reason for the effect of BST is that the BST layer can absorb oxygen vacancies or other point defects from the PZT layer and greatly improve its fatigue properties.