Ca/Sn concentration-dependent enhancement of barium titanate ferroelectric performance: a dielectric and microstructural study

Abstract

This work involved the synthesis of compositions of Ba0.95Ca0.05SnxTi1-xO3 (BCST) with varying amounts of Sn dopant (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1). A standard solid-state reaction approach was used to create all of the ceramic compounds. Each BCST composite’s microstructure, sintering, morphology, density, optical, and electrical characteristics were carefully examined, and the dielectric performance was optimized. In comparison to the unmodified composite, introducing varied amounts of Sn material into the BCST compound changed the crystal lattice vibrations and functional group locations. This result indicates that there are some variations in unit cell size, revealing that Sn+4 ions diffused effectively inside the lattice structure to produce BSCT composites. Further, SEM micrographs indicated proportionate changes in the homogenous structure and irregular forms as Sn concentration increased, as well as some variation in average grain size. As a consequence, by adding 0.08 mol% of Sn dopant, the crystallite size and average grain size were adjusted to 45.69 nm and 0.66 µm, respectively. Meanwhile, the 0.08-Sn specimen displayed a dielectric constant (Ɛ) with an optimum value of 5557 and a relative decrease in the Curie-Weiss constant. These results are attributed to the existence of various concentrations of Sn ions at the Ti-site of the BCT, which resulted in a compositionally disordered state. This disordered condition is essential for the production of dielectric compounds. Therefore, it is evident that modifying the amount of Sn doping added significantly enhanced the dielectric characteristics of the BCST composites created in this work. However, excessive Sn doping reduces the dielectric properties due to a reduction in tetragonal phase and an increase of disorders and charge fluctuations. Graphical Abstract