Chemical composition-induced evolution of the structure, domain and electrical properties of Sm-doped (1 - x )Pb(Ni 1/3 Nb 2/3 )O 3 - x PbTiO 3 .

As the two typical basic binary solid solutions of the relaxor-PbTiO 3 family, Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 (PMN-PT) has been widely investigated, whereas Pb(Ni 1/3 Nb 2/3 )O 3 -PbTiO 3 (PNN-PT) has not. Here, 1.5 mol% Sm-doped (1 - x )Pb(Ni 1/3 Nb 2/3 )O 3 - x PbTiO 3 , (1 - x )PNN- x PT:0.015Sm with x = 0.33-0.39, ceramics have been prepared and the chemical composition-induced evolution of crystal structure, domain, and electrical properties investigated systematically. With increasing PT content, evolution of the rhombohedral-tetragonal structure was observed. A rhombohedral-tetragonal morphotropic phase boundary occurred around x = 0.36-0.37, which showed a peak piezoelectric property with piezoelectric constant d 33 = 531 pC N -1 and planar electromechanical coupling factor k p = 0.37 at room temperature. At the same time, the x = 0.36 composition showed improved ferroelectric behavior with remanent polarization P r = 13.4 μC cm -2 and coercive field E c = 3.2 kV cm -1 . Interestingly, different from its PMN-PT counterpart, there is no temperature-driven phase transition between room temperature and the Curie temperature for (1 - x )PNN- x PT:0.015Sm. These parameters indicated that the PNN-PT system is worthy of more attention and is a promising platform for further development of high-performance piezo/ferroelectric materials.