Enhanced piezoelectric activity with good thermal stability and improved electrical resistivity in Ta Mn co doped CaBi4Ti4O15 high temperature piezoceramics
Abstract Aurivillius phase CaBi4Ti4 x (Ta2/3Mn1/3)xO15 (x 0 0.1) high temperature piezoelectric ceramics were fabricated using the conventional solid state reaction process. The effects of the Ta Mn co doping level on the structure, piezoelectric properties and electrical conduction behaviours of the as prepared CBT (CaBi4Ti4O15) ceramics were explored in detail. It was revealed that the Ta Mn co doping efficaciously enhanced the electrical performances of the CaBi4Ti4O15 ceramic, which may be due to optimisation of the crystal structure and a reduction in the oxygen vacancy concentration. The composition with x 0.04 presented superior electrical properties with an outstanding piezoelectric constant (d33) of 24 pC/N accompanied by a high Curie temperature (TC) of 793 degC, an optimised dielectric loss (tand) of 1.5% and an improved resistivity (r) of 4.96 x 108 O cm at 400 degC. Moreover, the ceramic exhibited impressive thermal stability with the d33 value maintaining 91.7% of its initial value at room temperature (25 degC) after being annealed at 600 degC for 2 h. The improved performance indicates that the Ta Mn co doped CaBi4Ti4O15 ceramic might be a promising candidate for piezoelectric device applications at elevated temperatures.