Preparation, structure, and electric properties of the Pb(Lu1/2Nb1/2)O3-Pb(Ni1/3Nb2/3)O3-PbTiO3 ternary ferroelectric system ceramics near the morphotropic phase boundary

0.30Pb(Lu1/2Nb1/2)O3-xPb(Ni1/3Nb2/3)O3-(0.70-x)PbTiO3(PLN-PNN-PT) ceramics with various PNN contents were prepared using a modified two-step columbite precursor method and characterized by X-ray diffraction (XRD), ferroelectric and dielectric measurements. The composition of 0.30PLN-0.31PNN-0.39PT exhibits excellent physical properties with d33 = 366pC/N, TC = 214 °C, ε′ = 3076, tan δ = 0.0225, Pr = 32.89μC/cm2 and Ec = 15.23KV/cm. The values of relaxor factor γ approaches 2 indicating diffuse character of PLN-PNN-PT ceramic. The dielectric behavior was discussed based on Curie-Weiss Law and Lorentz-type quadratic relationship. A transformation from relaxor ferroelectric to normal ferroelectric was demonstrated with PT content increasing in this ternary system.