Densification behavior and electrical properties of CuO-doped Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ternary ceramics

CuO modified Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) ternary relaxor based ferroelectrics with the composition near the morphotropic phase boundary were synthesized by two-step columbite precursor method. The introduction of CuO significantly improved the sinterability of PIN-PMN-PT ceramics, resulting in the full densification of samples at lower sintering temperatures. It also profoundly modified the crystal structure and fracture mode of the ceramics. Properly increasing CuO content led to the disappearance of rhombohedral-tetragonal phase transition, remarkably improved the Curie temperature (Tc), and made the ceramics more relaxorlike. The ternary ceramics doped with 0.25 wt% CuO possessed optimum piezoelectric properties (d33=584 pC/N, d33*=948 pC/N, and kp=0.68), high ferroelectric properties (Ec=9.9 kV/cm, and Pr=33.1 μC/cm2), low dielectric loss (tan δ=0.9%), and wider temperature usage range (Tc=225 °C). The obtained properties are much higher than those of previously reported PIN-PMN-PT based ceramics, indicating that CuO doped PIN-PMN-PT is a promising candidate for electromechanical applications with high performance and wide temperature/electric field usage ranges.