Energy harvesting, electrical, and magnetic properties of potassium bismuth titanate-based lead-free ceramics

In this research, the properties of bismuth potassium titanate modified by bismuth nickel titanate ceramics were investigated. XRD showed that all ceramics exhibited a single perovskite structure. The crystal structure changed from a tetragonal to a cubic phase with increasing modifier content. Average grain size decreased while the bulk density and hardness increased with the modifier. The improvement of mechanical properties was related to the change in microstructural and density. The 5 – 10 mol% ceramics showed the good electrical properties. The maximum dielectric properties (ε′ = 1763, tan δ = 0.0697) were obtained for the 10 mol% ceramic. The highest piezoelectric voltage constant (g₃₃ = 23.92 × 10⁻³ Vm/N) and the off-resonance figure of merit (FoM) for energy harvesting (~ 6.64 pm²/N) were obtained for the 5 mol% ceramic, which was ~ 5.0 times (or 399%) as compared to the pure BKT ceramic. The additive also produced an improvement in the magnetization-magnetic field hysteresis loop. The obtained results suggested that the additive not only enhanced the mechanical properties but also improved the ferroelectric, magnetic, and energy harvesting performances of the studied ceramics.