Microstructural and ferroelectric properties of rare earth (Ce, Pr, and Tb)-doped Na0.5Bi4.5Ti3O15 thin films

Abstract

Pure Na0.5Bi4.5Ti4O15 and rare earth-doped Na0.5Bi4RE0.5Ti4O15 (RE=Ce, Pr, and Tb) thin films were prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. X-ray diffraction and Raman scattering spectroscopy studies revealed that the thin films are crystallized in a single-phase Aurivillius structure with no additional phases. The rare earth-doped Na0.5Bi4RE0.5Ti4O15 thin films exhibited improved electrical and ferroelectric properties. Among the studied rare earth metal ions, the Tb3+ ion leads to a remarkable improvement in the ferroelectric properties. The use of the Tb3+ ion for doping resulted in a well-saturated ferroelectric hysteresis loop with a large remnant polarization (2Pr) of 40μC/cm2 and a low coercive electric field (2Ec) of 176kV/cm, measured at an applied electric field of 475kV in the Na0.5Bi4Tb0.5Ti4O15 thin film. Furthermore, the leakage current density of the Na0.5Bi4Tb0.5Ti4O15 thin film was one order of magnitude lower than that of the Na0.5Bi4.5Ti4O15 thin film.