Structure evolutions with enhanced dielectric permittivity and ferroelectric properties of Ba_(1−x)(La, Li)_xTiO₃ ceramics

Polycrystalline Ba_(1−x)(La_0.50Li_0.50)_xTiO₃ (0 ≤ x ≤ 0.12) ceramics are fabricated via the solid-state reaction technique to analyze their structure, excellent dielectric permittivity, and ferro/piezoelectric characteristics systematically. Powder x-ray diffraction has revealed the pure polycrystalline tetragonal symmetry for x ≤ 0.09 compositions. Rietveld refinement analysis has revealed the structure having a reducing tetragonality with increasing composition. A dense and compact ceramic with many grains having different size distributions has been perceived. The substitution of Li and La ions in BaTiO₃ unit cell lattice has increased the ambient temperature dielectric permittivity with reduced loss tangent from ~ 2000, ~ 0.019 (for x = 0) to ~ 5166, ~ 0.002 (for x = 0.09) at 1 MHz frequency. In addition, a high bipolar strain ~ 0.24% for x = 0.03 is obtained. The increase of dielectric permittivity with reduced loss tangent might be applicable for capacitor applications at ambient conditions.