Piezo-/dielectric properties of perovskite-structure high-temperature relaxor ferroelectrics: The Pb(Lu1/2Nb1/2)O3–Pb(Zn1/3Nb2/3)O3–PbTiO3 ternary ceramics

A new compositional system of relaxor ferroelectrics was investigated based on the high piezoelectricity Pb(Zn1/3Nb2/3)O3–PbTiO3 ferroelectric perovskite family. Compositions were fabricated near an estimated morphotropic phase boundary (MPB) of the Pb(Lu1/2Nb1/2)O3–Pb(Zn1/3Nb2/3)O3–PbTiO3 (PLZNT) ternary system by a two-step synthetic process. Their structures have been analyzed by means of X-ray diffraction technique. On the basis of X-ray powder diffraction, the morphotropic phase boundary (MPB) region for the ternary system was obtained. The Curie temperature TC of ternary system varied from 240 °C to 330 °C and the coercive fields Ecs > 10 kV/cm. The values of piezoelectric coefficients d33 vary in the range of 260–450 pC/N with different PZN contents. It is worth noting that the optimum compositions were located at MPB region but near the tetragonal phase. The new PLZNT ceramics exhibit wider range of TCs and Ecs, making it a promising material for high-powder ultrasound transducers using in a large temperature range.