Ferroelectric solid solutions based on (1-x)BaTiO3–xLi0.5Bi0.5TiO3 with colossal dielectric constant for metamaterial applications

Barium titanate powders of ~ 50 nm size were pre-synthesized using a hydrothermal technique to lower sintering and calcination temperatures of (1-x)BaTiO₃–xLi_0.5Bi_0.5TiO₃ solid solutions. The obtained powders of the solid solutions were analyzed using TEM and X-ray powder diffraction spectroscopy to indicate their properties. The Rietveld analysis was used to confirm the formation of ferroelectric tetragonal single-phase (1-x)BaTiO₃–xLi_0.5Bi_0.5TiO₃ solid solutions. The effects of varying concentrations of Li_0.5Bi_0.5TiO₃ on the structure and dielectric properties were investigated. The unit cell volume decreased with increasing Li and Bi concentration due to the smaller ionic radius of lithium compared to barium. Increasing lithium concentration caused the phase transition in barium titanate to blur, and a liquid phase formed at the grain boundaries, significantly reducing the sintering temperature. Increasing Li and Bi concentration led to a decrease in sintering temperature from 1240 °C (at x = 0.05) to 1100 °C (at x = 0.5).