Microstructure, ferroelectric and dielectric properties of sandwich structure for Na0.5Bi0.5TiO3 thin film modified with aliovalent substitution

Na0.5Bi0.5TiO3 (NBT)-based sandwich structure composed of Na0.5Bi0.5Ti0.98Nb0.02O3 (NBTNb) middle film and Na0.5Bi0.5Ti0.98Mn0.02O3 (NBTMn) buffer layer was fabricated on indium tin oxide/glass substrate via chemical solution deposition. X-ray diffraction measurement reveals the multilayered film can be crystallized into a phase-pure perovskite structure. The significant diode-like rectification effect as well as the switching of rectification direction are observed. A well-defined polarization–electric field hysteresis loop exhibits a large remanent polarization (Pr) of 25 μC/cm2. The dielectric tunability increases monotonously with the increasing of applied voltage and tends to be saturated with a maximum value of 28% at ±20 V. These results suggest that NBTNb thin film sandwiched by NBTMn buffer layer can effectively improve the electrical performances of NBT-based ferroelectric thin film.