Phase formation and dielectric properties of ferroelectric glass-ceramics in Na2O-BaO-Nb2O5-SiO2 system doped with Nd3+

Ferroelectric Glass-ceramics of the Na2O-BaO-Nb2O5-SiO2 system were obtained from controlled crystallization process performed on the parent glass of composition (24-x)Na2O-xBaO-26Nb(2)O(5)-50SiO(2) where x = 4 was selected. Nd2O3 doping was applied in the range 0-3 mol%. X-ray diffraction analysis indicated that NaNbO3 and NaBa2Nb5O15 crystals formed as two main crystalline phases. Their relative intensities varied with treatment temperature. Crystalline sizes of both NaNbO3 and NaBa2Nb5O15 calculated from XRD peak broadening were in nanoscale range. Increasing of doping content also gave a parent glass with higher bulk density. The dielectric constant measured at room temperature for glass-ceramic samples was found to be sensitive to the presence of NaBa2Nb5O15 phase. The results of the present work suggest that introduction of Nd3+ into Na2O-BaO-Nb2O5-SiO2 system not only alters the dielectric response but also changes the phase transition behaviors of the co-existant ferroelectric phases by suppressing the growth of the NaBa2Nb5O15 crystals.