Soft 및 Hard화 이온들이 함께 첨가된 PZT 세라믹스의 제조 및 압전물성

Abstract

Lead zirconate titanate (PbZrxTi1-x or PZT) ceramics are the most widely studied and technologically important ferroelectric materials. Especially, the solid solution composition located near the rhombohedral-tetragonal morphotropic phase boundary (MPB) possesses eminent piezoelectric characteristics. In particular, compositionally modified lead zirconate titanate (doped-PZT) ceramics with their improved electrical properties are widely utilized in the dielectric and piezoelectric applications.

In general, with the amount of dopant content, the compositional modification (doping) by single dopant leads the drastic variations of electrical properties of the PZT ceramics. Since properties are also changed by impurities in raw materials, it is difficult to reproduce and optimize the electrical performances. In the present study, to improve the reproducibility and to enhance the electrical properties of the MPB-PZT ceramics, a complex doping with two or more metal elements including both softeners and/or hardeners is adopted.

The prepared PZT ceramics modified with complex soft dopants of La3+ and Nb5+ showed that the piezoelectric properties were enhanced and stabilized with the compositional variations, e.g., the amount of dopants contents or the raw materials with purities, which made it possible to establish the higer reliability and reproducibility of the piezoelectric performancees. Unlike single (soft or hard) element doping, the complex doping of both the soft and hard ions caused various compensation effects for the piezoelectric properties of the PZT ceramics. The improved piezoelectric properties, i.e., enhanced Qm with remaining higher Kp were obtained in the PZT composition doped with La3+ and Fe3+.