Enhanced Electrical Properties of Novel Pb(Ni1/3Nb2/3)O3–BiScO3–PbTiO3 Ternary System near Morphotropic Phase Boundary

A novel xPb(Ni1/3Nb2/3)O3–(1-x)(0.30BiScO3–0.70PbTiO3) (PNN–BS–PT) ternary system was prepared by the columbite precursor method. The phase structure, microstructure, and electrical properties of ceramics of this system were investigated to identify the morphotropic phase boundary (MPB) composition of this system. The MPB with coexisting rhombohedral–tetragonal phases of PNN–BS–PT was located at approximately x=0.35, confirmed by their respective electric properties. With increasing PNN content, the coercive field EC, the Curie temperature TC, and the rhombohedral-to-tetragonal phase transition temperature TR–T were found to decrease and showed nearly linear dependences on their compositions. The enhanced properties were achieved in the MPB composition with x=0.35, which are as follows: dielectric constant εr=3160 (1 kHz), piezoelectric coefficient d33=490 pC/N, and electromechanical coupling factor kp=0.44. In addition, a large bipolar strain on the order of 0.6% was achieved for the composition when an electrical field E=40 kV/cm was applied.