Rietveld analysis, optical, and ferroelectric properties of (1 -x) (Na_(0.97)K_(0.03))NbO_3-xBaTiO_3(x=0.1,02) ceramics synthesized by solid-state reaction method

摘要

(1-x)(Na0.97K0.03)NbO3-xBaTiO(3) ceramics [NKN-xBT, (x=0.1, 0.2)] were synthesized by solid-state sintering process. The powder X-ray diffraction results showed that the crystalline symmetry of the sintered samples was transformed from tetragonal (x=0.1) to cubic (x=0.2) symmetry. Morphological properties of NKN-xBT (x=0.1, 0.2) were investigated by scanning electron microscopic images. Energy band gap was studied by UV-visible spectroscopy, which is found to decrease with the addition of Ba2+ content in the host lattice. Ferroelectric behavior of the samples was examined by polarization versus electric field hysteresis loop measurements, which is found that the tetragonal phase exhibits enhanced properties. The values of remnant polarization, maximum polarization and coercive field for x=0.1 is found to be 12.25C/cm(2), 14.38C/cm(2) and 6.56kV/cm, respectively. Based on the previous reports modified NKN-xBT (x=0.1, 0.2) ceramics considered as promising lead-free candidates for ferroelectric and dielectric components.