Structural, dielectric and piezoelectric properties of SrBi2Nb2O9 and Sr0.8Bi2.2Nb2O9 ceramics

Lead free polycrystalline materials SrBi2Nb2O9 and Sr0.8Bi2.2Nb2O9 were synthesized by conventional solid-state reaction process. X-ray diffraction studies confirm the single phase compound in the orthorhombic crystal system. Raman spectroscopy was used to understand the lattice vibrational characteristics of sintered pellets for SrBi2Nb2O9 and Sr0.8Bi2.2Nb2O9 ceramics. The morphology was observed by scanning electron microscopy. The Sr-deficient and Bi-excess SBN (deficient Strontium bismuth niobate: Sr0.8Bi2.2Nb2O9) was found to have better density and least porosity. The dielectric and electrical response of SBN ceramics have been studied in the frequency range of 20 Hz–1 MHz and in the temperature range 30–500 °C. The transition temperature (Tc) was found to gradually increase from 401 °C for SrBi2Nb2O9 (SBN1A) to 440 °C for Sr0.8Bi2.2Nb2O9 (SBN2A). The ac conductivity (σac) of both samples SBN1A and SBN2A was found to follow the universal Joncher׳s power law. The piezoelectric coefficient (d33) 20 pC/N has been achieved for Sr deficient and Bi excess SBN.