Synthesis, crystal structure and ferroelectric properties of SrBi₂Nb₂O₉ embedded in a 50 % Li₂B₄O₇ glass matrix

Abstract

Transparent glass sample [50Li₂B₄O₇–50(SrO–Bi₂O₃–Nb₂O₅)] (mol %) was prepared by the melt-quenching technique. The glassy nature of the as-prepared sample was established by Differential scanning calorimetry (DSC). Ferroelectric SrBi₂Nb₂O₉ (SBN) embedded in a 50 % Li₂B₄O₇ glass matrix was produced by heat-treating the as-prepared sample at 874 K (HT874) for 6 h. The X-ray structural analysis showed that SrBi₂Nb₂O₉ crystallizes in the orthorhombic (A2₁am) with a = 5.5104, b = 5.5096 and c = 25.0794 Å. Infrared spectroscopy studies corroborate the observation of SrBi₂Nb₂O₉ phase formation. The dielectric properties have been studied in the frequency range of 120 Hz to 100 k Hz at various temperatures (300–815 K). The high frequency dielectric constant $\left( {\varepsilon_r^{\prime }} \right)$ shows a peak at T_c (743 K). The exponent n(T) and the coefficient A(T) in the Jonscher’s expression were found to be minimum and maximum respectively at the Curie temperature (T_c). AC conductivity measurements for present sample were reported.