Abstract
La- and Nd-substitutions for A-site of Bi in natural-superlattice structure of Bi3TiNbO9-Bi4Ti3O12 (BTN-BIT) films have been successfully carried out to reduce the coercive field (E c) and enlarge the remanent polarization (P r). These films have been grown on Pt(100)/TiO2/SiO2/Si and Pt(111)/TiO2/SiO2/Si heated at 550°C by pulsed laser deposition. X-ray photoelectron spectroscopy analysis shows that chemical state and stability of the Bi ions in the films. The La substitution has increased P r, but decrease E c and their twice values are 52 μ C/cm2 and 220 kV/cm, respectively. The 2P r and 2E c of the BTN-BIT:Nd0.5 film have been enhanced and are 70 μ C/cm2 and 370 kV/cm, respectively. A-site substitutions of La and Nd are effective to control the hysteresis characteristics in natural-superlattice-structured BTN-BIT thin films.