Large enhancement of piezoelectric properties and resistivity in Cu/Ta co‐doped Bi 4 Ti 3 O 12 high‐temperature piezoceramics

In this study, the electrical properties of Bi 4 Ti 3 O 12 ‐based Aurivillius‐type ceramics were tailored by a B‐site co‐doping strategy combining high valence Ta 5+ and low valence Cu 2+ . A series of Bi 4 Ti 3− x (Cu 1/3 Ta 2/3 ) x O 12 (BTCT) ( x = 0, 0.005, 0.01, 0.015, 0.02, 0.025, and 0.03) ceramics were prepared by the conventional solid‐state reaction method. The effect of Cu/Ta co‐doping on the crystal structure, microstructure, dielectric properties, piezoelectric properties, ferroelectric properties, and electrical conductivity of these ceramics was systematically investigated. Co‐doping significantly enhanced the piezoelectric properties and DC electrical resistivity of the resulting composites. The optimized comprehensive performances were obtained at x = 0.015 with a large piezoelectric coefficient (34 pC/N) and a relatively high resistivity of 9.02 × 10 6 Ω cm at 500°C. Furthermore, the ceramic also exhibited stable thermal annealing behaviors and excellent fatigue resistance. The results of this study demonstrated great potential of the Cu/Ta co‐doped Bi 4 Ti 3 O 12 ceramics for high‐temperature piezoelectric device applications.