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Effects of lanthanum doping on the dielectric, piezoelectric properties and defect mechanism of PZN–PZT ceramics prepared by hot pressing
Author(s) -
Zeng X.,
Ding A. L.,
Deng G. C.,
Liu T.,
Zheng X. S.
Publication year - 2005
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200420049
Subject(s) - materials science , dielectric , doping , phase boundary , pyrochlore , ferroelectricity , lanthanum , tetragonal crystal system , electrical resistivity and conductivity , hot pressing , ceramic , dielectric loss , phase (matter) , analytical chemistry (journal) , permittivity , composite material , inorganic chemistry , chemistry , optoelectronics , organic chemistry , engineering , chromatography , electrical engineering
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)