Effects of Bi(Zn_2/3Nb_1/3)O₃ Modification on the Relaxor Behavior and Piezoelectricity of Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃...

Relaxor lead magnesium niobate (PMN)-based materials exhibit complex structures and unusual properties that have been puzzling researchers for decades. In this paper, a new ternary solid solution of Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃-Bi(Zn_2/3Nb_1/3)O₃ (PMN-PT-BZN) is prepared in the form of ceramics, and the effects of the incorporation of BZN into the PMN-PT binary system are investigated. The crystal structure favors a pseudocubic symmetry and the relaxor properties are enhanced as the concentration of BZN increases. The relaxor behavior and the related phase transformations are studied by dielectric spectroscopy. A phase diagram mapping out the characteristic temperatures and various states is established. Interestingly, the piezoelectricity of the PMN-PT ceramics is significantly enhanced by the BZN substitution, with an optimal value of d₃₃ reaching 826 pC/N for 0.96[0.7Pb(Mg_1/3Nb_2/3)O₃-0.3PbTiO₃]-0.04Bi(Zn_2/3Nb_1/3)O₃. This paper provides a better understanding of the relaxor ferroelectric behavior, and unveils a new relaxor-based ternary system as piezoelectric materials potentially useful for electromechanical transducer applications.