Effects of (In + Nb) co-doping on the microstructure and electrical properties of Bi0.5Na0.5TiO3 ceramics

This study delves into the effects of (In + Nb) co-doping on the microstructure and electrical properties of Bi0.5Na0.5TiO3 (BNT) ceramics, focusing on phase transitions, defect chemistry, and pyroelectric performance. The research reveals that co-doping induces a shift from a predominantly rhombohedral phase to a tetragonal-dominated structure, accompanied by the emergence of minor Bi2O3 and In2O3 secondary phases at higher doping levels. The study also examines the impact of co-doping on grain size, lattice distortion, and the formation of defect dipoles. Dielectric measurements show a transition from normal ferroelectric behavior to relaxor-like characteristics, with a reduction in dielectric constant and loss. Pyroelectric measurements highlight that the ceramic with x = 0.01 exhibits the most balanced performance, with peak values of p = 2.57×10−3 C·m−2·°C−1, Fi = 9.152×10−10 m/V, Fv = 0.1205 m2/C, and Fd = 3.982×10−5 Pa−1/2. The enhancement in pyroelectric performance is attributed to the synergistic regulation of defect oxygen and Ti3+ concentrations, as well as the formation of defect dipoles. The study concludes that (In, Nb) co-doping effectively optimizes the properties of lead-free pyroelectric materials, offering a promising approach for developing eco-friendly devices.