Influence of Al(2)O(3) nanoparticle doping on depolarization temperature, and electrical and energy harvesting properties of lead-free 0.94(Bi(0.5)Na(0.5))TiO(3)–0.06BaTiO(3) ceramics

In this research article, the effects of Al(2)O(3) nanoparticles (0–1.0 mol%) on the phase formation, microstructure, dielectric, ferroelectric, piezoelectric, electric field-induced strain and energy harvesting properties of the 0.94(Bi(0.5)Na(0.5))TiO(3)–0.06BaTiO(3) (BNT–6BT) ceramic were investigated. All ceramics have been synthesized by a conventional mixed oxide method. The XRD and Raman spectra showed coexisting rhombohedral and tetragonal phases throughout the entire compositional range. An increase of the grain size, T(F–R), T(m), ε(max) and δ(A) values was noticeable when Al(2)O(3) was added. Depolarization temperature (T(d)), which was determined by the thermally stimulated depolarization current (TSDC), tended to increase with Al(2)O(3) content. The good ferroelectric properties (P(r) = 32.64 μC cm(−2), E(c) = 30.59 kV cm(−1)) and large low-field d(33) (205 pC N(−1)) values were observed for the 0.1 mol% Al(2)O(3) ceramic. The small Al(2)O(3) additive improved the electric field-induced strain (S(max) and [Image: see text]). The 1.0 mol% Al(2)O(3) ceramic had a large piezoelectric voltage coefficient (g(33) = 32.6 × 10(−3) Vm N(−1)) and good dielectric properties (ε(r,max) = 6542, T(d) = 93 °C, T(F–R) = 108 °C, T(m) = 324 °C and δ(A) = 164 K). The highest off-resonance figure of merit (FoM) for energy harvesting of 6.36 pm(2) N(−1) was also observed for the 1.0 mol% Al(2)O(3) ceramic, which is suggesting that this ceramic has potential to be one of the promising lead-free piezoelectric candidates for further use in energy harvesting applications.