Improvements of the ferroelectric properties of high-valence Tb-doped Bi4Ti3O12 thin film grown by sol-gel method

High-valence Tb-doped bismuth titanate (Bi3.6Tb0.4Ti3O12) (BTT) ferroelectric film was fabricated on Pt/TiO2/SiO2/Si (100) substrate by sol-gel technique. The BTT film had a polycrystalline perovskite structure with uniform and dense surface morphology. At a maximum applied electric field of 540 kV/cm, a remnant polarization of 59.8 mu C/cm(2) and coercive field of 298 kV/cm were observed through ferroelectric measurements. The measured dielectric constant and loss of the film were 490 and 0.047 at a frequency of 1 MHz. The film showed excellent anti-fatigue characteristics with less than 2% degradation in switchable polarization after 1.0 x 10(10) switching cycles. These improved ferroelectric properties may be attributed to the structural distortion and the low concentration of oxygen vacancy associated with Tb substitution for Bi. (C) 2009 Elsevier B.V. All rights reserved.