Morphotropic phase boundary and electrical properties of lead-free (K0.5Bi0.5)TiO3-Bi(Ni0.5Ti0.5)O3 relaxor ferroelectric ceramics

Lead-free relaxor ferroelectric ceramics (1-x)(K0.5Bi0.5)TiO3-xBi(Ni0.5Ti0.5)O-3 were prepared by a conventional solid-state route, the phase transition behavior and corresponding electrical properties were investigated. A typical morphotropic phase boundary (MPB) between rhombohedral and tetragonal ferroelectric phases was identified to be in the range of 0.05 < x < 0.07 where the optimum piezoelectric and electromechanical properties of d(33)=126 pC/N and k(P)=18% were achieved. Most importantly, a high Curie temperature similar to 320 degrees C, around which the material shows a typical relaxor ferroelectric behavior characterized by the presence of diffuse phase transition and frequency dispersion, was obtained in MPB compositions, significantly higher than those of some existing MPB lead-free titanate systems. These results demonstrate a tremendous potential of the studied system for device applications. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.