  Ferroelectric glass-ceramics are promising composite materials with dual
properties, of high dielectric permittivity and high dielectric breakdown
strength. In this context, new phosphate glass-ceramics 2BaO-0.5Na2O
2.5[(1-x)Nb2O5 xWO3]-1P2O5 (x=0, 0.1, 0.2, 0.3 and 0.4) designated as B0, B1,
B2, B3, B4 respectively, were prepared by the controlled crystallization
technology and then crystallized at high temperature of 760 {\deg}C for 10
hours. Subsequently, the obtained glass-ceramics were studied by Differential
Scanning Calorimetry (DSC), X-ray powder diffraction (XRD), Raman, impedance
spectroscopy, and the P-E hysteresis loops. All of these techniques allowed the
identification of Ba2Na4W2Nb8O30 phase with tungsten bronze structure embedded
in the glassy matrix. The density of glass-ceramics was found to increase with
increasing tungsten content to reach a maximum at x =0.3 and then decreases.
Dielectric and conductivity parameters were found to be governed by the
presence of oxygen vacancies. Room temperature energy storage property which
depends on the composition X, was performed using P-E hysteresis loops of the
glass-ceramics. The optimum discharge density was obtained for B3 with an
energy efficiency of 73.77%.

Materials Science