Electrical properties of Bi_2.99(Li_0.5Sm_0.5)_0.01Ti_1-x(Mn_1/3Ta_2/3)_xNbO₉ high-temperature piezoelectric ceramics via oxygen vacancy defects tailoring

Tribismuth titanium niobium oxide (B₃TiNbO₉, BTNO) is one of the Aurivillius phases with the highest Curie temperature (T_c), but its piezoelectric coefficient (d₃₃) is poor. When x = 0.045, high-temperature piezoelectric ceramics with d₃₃ of 11.9 pC/N and T_c of 916.7 °C were prepared by (Mn_1/3Ta_2/3)^(4+ω)+ modification of Ti⁴⁺ at B-site of Bi_2.99(Li_0.5Sm_0.5)_0.01Ti_1-x(Mn_1/3Ta_2/3)_xNbO₉. The substitution will aggravate the distortion of BO6 octahedron due to the displacement of oxygen ions. The existence of Mn³⁺ in the dopant will act as an oxygen vacancy trap and then increase the resistivity. As a result, BTNO ceramics have enhanced piezoelectric properties as well as temperature and cycle stability. This work provides a theoretical basis for better high-temperature piezoelectric properties of A/B co-doped Aurivillius phase ceramics in the future.