Effects of lanthanum doping on the dielectric, piezoelectric properties and defect mechanism of PZN-PZT ceramics prepared by hot pressing
✍ Scribed by Zeng, X. ;Ding, A. L. ;Deng, G. C. ;Liu, T. ;Zheng, X. S.
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 188 KB
- Volume
- 202
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
Abstract
The structure and electrical properties of Pb(Zn~1/3~Nb~2/3~)~0.3~(Zr~0.55~Ti~0.45~)~0.7~O~3~–__x__La ceramics system by hot pressing with the composition near to the morphotropic phase boundary (MPB) were investigated as a function of La doping content. PZN–PZT specimens shifted from rhombohedral phase towards tetragonal phase with increasing La doping. Dielectric spectroscopy showed that La doping decreased dielectric permittivity maximum remarkably, and increased the degree of diffuse phase transition (DPT) with lower ferroelectric phase transition temperature. The growth of 1:1 chemically ordered domains through La doping was considered the cause of the dielectric dispersion. The high piezoelectric coefficient, d~33~ (716 pC/N), and electromechanical coupling factor, k~p~ (0.62) were obtained in spite of existence of the pyrochlore phase. Oxygen vacancy conduction was the dominant mechanism. La doping reduced the concentration of oxygen vacancies, thus increased the electrical resistivity. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)