Effect of Composition on the Structural and Electrical Properties of PMN-PT [Pb(Mg1/3Nb2/3)O3-PbTiO3] Based Ceramics

Polycrystalline samples of (1-x)PMN-(x)PT [Pb(Mg1/3Nb2/3)O3-PbTiO3] (x=0.30 to 0.39) piezoelectric ceramics were synthesized via a solid-state reaction route. Based on the previous literature, 5% mol excess MgO was used in order to eliminate the formation of unwanted pyrochlore phase. Microstructural and compositional analyses have been carried out using scanning electron microscope (SEM) and X-ray diffraction (XRD). Besides, electrical characterization was performed by using impedance analyzer and Berlincourt d33-piezometer. Formation of the pyrochlore phase was eliminated significantly by using excess MgO and one-step calcination method. XRD patterns indicated a transition from rhombohedral to tetragonal phase with increasing PT content. Effect of altering PMN-PT composition on the piezoelectric and dielectric properties was also investigated. The results showed that the rhombohedral and tetragonal phases coexisted at 0.30 x 0.39 and the ceramic with x=0.33 possessed the optimum properties (d33=480 pC/N, KT=4556, kp=0.505, tanδ=2.9%, Qm=59.6, Tc=150 °C).