Insights into the dielectric and luminescent properties of Na(0.5)Pr(0.003)Bi(0.497-x)La(x)TiO3 synthesized by the Pechini method.

Lead-free ferroelectric ceramics based on the Na(0.5)Bi(0.5)TiO3 system, in solid solution with Pr(3+) and La(3+), are synthesized by the Pechini method at low temperature. The powders calcined at 700 °C are found to be below 200 nm in mean crystal size. The dielectric properties reveal a diffuse phase transition. In Na(0.5)Bi(0.5)TiO3 ceramics the rhombohedral to tetragonal transition temperature (T(R-T)) appears near 190 °C, and the Curie temperature (T(C)) at 280 °C. These transitions are shifted when Pr(3+) and La(3+) cations are introduced into the lattice. The ferroelectric properties are also affected, causing the remnant polarization and coercive field to diminish with the increase in La(3+) content. In addition, the piezoelectric properties decrease in the same way with La(3+) concentration. Finally, the red luminescence of Pr(3+) is improved when lanthanum concentration is increased.