Enhancing Speed and Stability of Polarization Reversal in Predominantly a/b‐Axes‐Oriented Bi₄Ti₃O₁₂ Thin Films Deposited on Pt/Ti/SiO₂/Si

Abstract

Bi4Ti3O12‐based thin films of a/b‐axes orientation grown on standard‐type Pt/Ti/SiO2/Si substrates are desirable for designing reliable ferroelectric devices. Herein, a/b‐axes‐oriented and randomly oriented Bi4Ti3O12 thin films are deposited on Pt/Ti/SiO2/Si through a sol–gel process. As expected, the a/b‐axes‐oriented films show a higher remnant polarization than that of randomly oriented films. The characteristic time τ of domain reversal in 74% a/b‐axes‐oriented Bi4Ti3O12 films is 1.1 ms, notably shorter than that (τ > 2.5 ms) for randomly oriented films. The dynamic hysteresis scaling relations of the randomly oriented 56% and 74% a/b‐axes‐oriented Bi4Ti3O12 films take the forms of ⟨A⟩ ∝ f−0.106E01.667, ⟨A⟩ ∝ f−0.035E00.952, and ⟨A⟩ ∝ f−0.026E00.600, respectively. The difference indicates that domain reversal in Bi4Ti3O12 films of predominant a/b‐axes orientation exhibits higher stability compared with randomly oriented Bi4Ti3O12 films under varying electric fields E(E0, f). The enhancing speed and stability of polarization reversal in predominantly a/b‐axes‐oriented Bi4Ti3O12 films can be understood in terms of their layered‐perovskite structure, large columnar grains, oxygen vacancies mobility, domain states, and polarization switching mechanism.