Na0.5Bi0.5(Ti0.98Zr0.02)O3 thin film with improved performance by modifying annealing atmosphere and Zr doping content

Annealing atmosphere and ion-doping content are two important parameters affecting the microstructure as well as electrical properties of Na0.5Bi0.5TiO3 (NBT)-based thin film. In this paper, polycrystalline Na0.5Bi0.5(Ti0.98Zr0.02)O3 (NBTZr0.02) thin films were firstly selected to be annealed under N2, O2 and air, respectively. Enhanced insulating and ferroelectric properties can be obtained for the NBTZr0.02 under N2 due to the better crystallinity with high densification. On the basis of this result, a series of Na0.5Bi0.5(Ti1−xZrx)O3 (NBTZrx) (x = 0, 0.01, 0.02, 0.04) films were synthesized under N2 and the effects of Zr4+ doping content on crystalline, ferroelectric and dielectric properties were characterized. X-ray diffraction analysis reveals that all the NBT thin films with Zr4+-doping show phase-pure perovskite structure. Compared with the NBTZrx (x = 0, 0.01, 0.04) thin films, NBT with 2 mol.% Zr4+ doping content exhibits better ferroelectricity with a remanent polarization (Pr) of 16.4 μC/cm2 and right-turning gap. Also, the dielectric constant (εr) and dissipation factor (tan δ) versus frequency exhibit small dispersion tendency with a εr of 410 and tan δ of 0.03 at 100 kHz.