Improvements of the ferroelectric properties of high-valence Tb-doped Bi_4Ti_3O_(12) thin film grown by sol-gel method

摘要

High-valence Tb-doped bismuth titanate (Bi_(3.6)Tb_(0.4)Ti_3O_(12)) (BTT) ferroelectric film was fabricated on Pt/TiO_2/ SiO_2/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 μC/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× 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.