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-26Nb₂O₅-50SiO₂ 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.