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

概要

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Material design to achieve a f high dielectric constant of ${\varepsilon _{33}}^{\text{T}}/\varepsilon _{0}>5{,}000$ and a large planar-mode electromechanical coupling factor (EMCF) of $k_{\text{p}}>65$% near the morphotropic phase boundary (MPB) in the multicomponent system of Pb(Sc1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-Pb(Ni1/3Nb2/3)O3-(Pb,Ba,Sr)(Zr,Ti)O3 (PSN-PMN-PNN-PBSZT) ceramics was investigated. To obtain the MPB composition of the multicomponent system, a smart material design was applied to predict Curie temperature ($T_{\text{c}}$) and exact TiO2 content in the system. In addition, to realize a high dielectric constant and a large EMCF, a low-mass (LM) B-site ion model and a B-site disordering model in lead perovskite were applied. To enhance disordering of the B-site ions, we focused on the complex perovskite system ceramics PSN-PMN-PNN-PBSZT, which consist of three A-site ions, Pb, Ba and Sr, and six LM B-site ions, those of Sc, Mg, Ni, Nb, Ti and Zr. Dielectric constants of ${\varepsilon _{33}}^{\text{T}}/\varepsilon _{0}=5{,}500$, a planar-mode EMCF of $k_{\text{p}}=72$%, a piezoelectric constant of $d_{33}=850$ pC/N and $T_{\text{c}}=153$°C were confirmed in the PSN-PMN-PNN-PBSZT ceramics near the MPB by utilizing the material design procedure.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2005-09-15