Abstract:
In this work, we investigated the consequence of Sr2+ substitution on the structural, morphological, dielectric, ferroelectric, piezoelectric, and optical properties of barium titanate (BT) prepared by the modified solid-state reaction route. The formation of a single-phase perovskite structure for pure and Sr2+ doped BT i.e. Ba1-xSrxTiO3 (BST) for x = 0, 0.03, 0.05, and 0.08, was confirmed by the X-ray diffraction (XRD) patterns. Structural refinement showed a reduction in unit cell volume and c/a ratio with Sr2+ substitution. The Raman spectroscopy of all the compositions agreed well with the XRD data. The presence of undercoordinated Ti3+ ions was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis. The average grain size increased up to BST-3 (x = 0.03) and then decreased linearly. The tetragonal to cubic phase transition temperature decreased by rising Sr2+ content. The diffuseness parameter increased with Sr2+ content and was found to be maximum for BST-8 (x = 0.08). The highest dielectric constant of 5005 had been found for BST-3 due to its large crystallite and average grain size. The energy storage efficiency decreased with Sr2+ substitution. For each composition, the storage efficiency was better than 68%, making them appropriate for use in high-density capacitors. The highest piezoelectric charge coefficient = 122 pC/N had been found for BST-3. For Sr2+ doped BT, the optical bandgap ranged from 1.97 to 2.32 eV. The indirect bandgap enlarged with increasing doping concentration. The bandgap of individual compositions was lower than that reported in the literature due to the existence of the disorder and can find applications in optoelectronics.