Investigations on structure, dielectric and ferroelectric properties of SrBi2Ta2O9 ceramic via A-site defect engineering

Yttrium-modified bismuth-layered ferroelectric SrBi2Ta2O9 (SBT) with general formula SrBi2-xY3x/4Ta2O9 (where x = 0.00, 0.025, 0.05, 0.075 and 0.10) are prepared by mixed oxide route. The structural, dielectric, ferroelectric and conductivity behavior of the above compounds for each composition of Y is discussed. The formation of monophase materials is noted from the X-ray diffraction pattern. The structure of the grains is studied using Scanning electron microscopy. The variation of the dielectric permittivity with temperature at some particular frequencies manifests a diffuse order phase transition with reduced T-c (ferroelectric transition temperature) and epsilon(r) (relative permittivity) with respect to higher concentration of Y. The ferroelectric properties in the materials are confirmed using hysteresis (P-E) loops. The remnant polarization of the materials is found to increase with the addition of Y while the coercive field follows the reverse trend.