Structural and Ferroelectric Properties of Bi_4−xY_xTi₃O₁₂ Films

Abstract

Yttrium-substituted Bi_{4 - x}Y_xTi₃O₁₂ (x = 0.00, 0.10, 0.30, 0.50, 0.75, 1.00) polycrystalline thin films were synthesized by metal-organic decomposition (MOD) method. Ferroelectric measurements revealed that the Bi₄Ti₃O₁₂ films substituted by Y with appropriate ratios could have higher remnant polarization (Pr) and significantly improved fatigue behavior compared with BTO. The remnant polarization of the Bi_3.50Y_0.50Ti₃O₁₂ capacitor reached 10 μC/cm² at an applied field about 120 kV/cm with nearly fatigue free property up to 10¹⁰cycles. XRD patterns show a little impurity phases as well as Aurivillius phase in the crystallization process with different annealing temperature. Perhaps it induced the poor leakage current properties.

Keywords:

• Bi_{4 - x}Y_xTi₃O₁₂
• ferroelectric properties
• microstructure

ACKNOWLEDGMENT

This work was supported by the National Science Foundation of China (No. 90207027, 10021001), the 973 Project of MOST (2002CB613303) of China, and Jiangsu Natural Science Foundation (No. BK 2002410).