Effect of La doping on microstructure and ferroelectric properties of Bi₄Ti₃O₁₂ thin films prepared by sol-gel method

Abstract

The Bi₄Ti₃O₁₂ and Bi_3.25La_0.75Ti₃O₁₂ thin films were prepared on the Pt/Ti/SiO₂/Si substrate using the sol-gel method. The effect of La doping on the microstructure and ferroelectric properties of Bi₄Ti₃O₁₂ films were investigated. Both the Bi₄Ti₃O₁₂ and Bi_3.25La_0.75Ti₃O₁₂ thin films exhibited typical bismuth layered perovskite structure. The 2Pr (remanent polarization) value of Bi_3.25La_0.75Ti₃O₁₂ thin films is 18.6 μC/cm², which is much larger than that of Bi₄Ti₃O₁₂ thin films. And the Bi_3.25La_0.75Ti₃O₁₂ films show fatigue-free behavior, while the Bi₄Ti₃O₁₂ thin films exhibit the fatigue problem. The mechanism of improvement of La doping was discussed.

Keywords

ferroelectric properties / sol-gel preparation / Bi₄Ti₃O₁₂ thin films / Bi_3.25La_0.75Ti₃O₁₂ thin films / La doping / fatigue

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