Significantly improved Curie temperature and electrical properties of Sm-doped Pb(Ni_1/3Nb_2/3)O₃-PbZrO₃-PbTiO₃ by...

Pb(Ni_1/3Nb_2/3)O₃-PbZrO₃-PbTiO₃ (PNN-PZ-PT) is one of the typical relaxor-PT piezoelectric systems. In order to further improve its Curie temperature (T_c) and piezoelectric properties, nominal Pb(Mg_1/3Nb_2/3)O₃ (PMN) is introduced into 2mol% Sm-doped 0.36PNN-0.28PZ-0.36PT to form a (0.36 - x)PNN-xPMN-0.28PZ-0.36PT:0.02Sm (x = 0-0.24) quaternary solid solution. The phase, microstructure, domain structure, and electrical properties of the solid solution ceramics were investigated systematically. All the samples exhibit a single phase perovskite structure and are situated around the rhombohedral-tetragonal morphotropic phase boundary. With increasing x, the T_c increases gradually, while the piezoelectric coefficient d₃₃ increases initially and decreases subsequently, reaching a peak value of 725 pC N^-1 at around x = 0.15. In particular, this optimal composition illustrates high performance with T_c = 176 °C, planar electromechanical coupling factor k_p = 0.63, remanent polarization P_r = 30 μC cm^-2, and coercive field E_c = 8.9 kV cm^-1. This study illustrates the viability of incorporating PMN into PNN-PZ-PT to optimize the comprehensive electrical properties, potentially offering a valuable guide for developing high performance relaxor-PT materials.