Piezoelectric Properties of Niobium-Doped [Pb(Sc_1/2Nb_1/2)_1-xTi_x]O₃ Ceramics Material near the Morphotropic Phase Boundary

The physical and electrical properties of Pb[(Sc_1/2Nb_1/2)_1-xTi_x]O₃ (x=0.40–0.45)+0.01 PbNb₂ O₆ piezoelectric polycrystalline ceramic materials near the morphotropic phase boundary (MPB) were investigated. The maximum dielectric constant (ε₃₃ ^T/ε₀=3200) and maximum piezoelectric constant (d₃₃=590×10^-12 m/V) were found at x=0.435, where the coupling factors were k _p=67 %, k₃₁=41 %, and k₃₃=74 %. The maximum electromechanical coupling factors, (k _p=71 %, k₃₁=44 %, and k₃₃=77 %) were found at x=0.420, where ε₃₃ ^T/ε₀=2080 and d₃₃=480×10^-12 m/V were obtained. The x=0.420 composition exhibited the largest electromechanical coupling factor of all binary piezoelectric ceramics systems so far reported, including the most widely used conventional ceramic, Pb(Zr_1-x, Ti_x)O₃.