Published online by Cambridge University Press: 10 February 2011
Thin films of ferroelectric (SrBi2Ta2O9)x(Bi3TiNbO9)1-x layered structure (for x = 0.0, 0.2, … 1.0) were prepared by a metal organic solution deposition method on Pt/TiO2/SiO2/Si substrates. Raman spectroscopy, X-ray diffraction, atomic force microscopy (AFM), and electrical characterization techniques were utilized to study the inclusion of SrBi2Ta2O9 (SBT) in the Bi3TiNbO9 (BTN) system. The Raman spectra show frequency shifts and broadening of modes as x increases from 0.0 to 0.4, which are related to the nature of Sr and Bi in the A-sites, and Ta, Ti, and Nb in the B-sites. Smooth surfaces without any cracks or defects were evidenced in each of these films by AFM. These images also indicate that the grain size in the films increases with increasing SBT content in the BTN compound. Electrical measurements show that the remanent polarization (Pr) and the coercive field (Ec) values in the x=0.0 film (2 μC/cm2 and 30 kV/cm, respectively) increase to 12.5 μC/cm2 and 125 kV/cm for x=0.6. A decrease in these parameters was found for higher compositions.