High Dielectric Constant and Large Electromechanical Coupling Factor Relaxor-Based Piezoelectric Ceramics

Abstract

Lead-perovskite multicomponent system ceramics Pb(Sc1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-(Pb,Sr)(Zr,Ti)O3 (PSN-PMN-PNN-PSZT) with high dielectric constant ε33T/ε0=7,200 and large sliver mode electromechanical coupling factor (EMCF) k33'=69% near the morphotropic phase boundary (MPB) were synthesized by a conventional solid-state-reaction process. To obtain high dielectric constant ε33T/ε0>7,000, a large EMCF and piezoelectric constant materials, a low-molecular-mass (LMM) B-site ion model in lead perovskite is applied to realize better dielectric and piezoelectric properties. We focused on complex perovskite system ceramics PSN-PMN-PNN-PSZT, which consist of four LMM B-site elements, such as, Sc, Mg, Ni and Nb. The maximum dielectric constants, ε33T/ε0=7,200 and ε33S/ε0=3,200, are confirmed in the PSN-PMN-PNN-PSZT ceramics. These ceramic show an planar-mode EMCF kp=69%, piezoelectric constant d33=940 pC/N and Curie temperature Tc=135°C. The dielectric and piezoelectric properties of these ceramics are studied for the ultrasonic medical array transducer application.