Enhanced electromechanical properties and conduction behaviors of Aurivillius Bi₄Ti_2.95(B_1/3Nb_2/3)_0.05O₁₂ (B=Mg, Zn, Cu) ceramics

(B_1/3/Nb_2/3) (B=Mg, Zn, Cu) co-substituting for Ti⁴⁺ in B-site of Bi₄Ti₃O₁₂-based Aurivillius ceramics were prepared to improve the piezoelectric properties. The electrical properties and conduction mechanisms of them were investigated. The activation energy related with the electrical relaxation determined from the electric modulus spectra was 0.71 eV and the electrical conductivity decreased dramatically by (Mg_1/3/Nb_2/3)-doping, due to the enhanced structural distortion and the decrease in oxygen vacancy concentration. The (Mg_1/3/Nb_2/3)-substituted specimen with a Curie point of 686 °C and a large field-induced strain of 0.061% as well as a higher remnant polarization of 12.9 μC/cm² could be a promising material for high-temperature lead-free piezoelectric applications.