Enhanced diffuse phase transition and defect mechanism of Na-doped Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} relaxor ferroelectrics
- Department of Materials Science and Engineering, and Laboratory for Physical Chemistry of Dielectric Materials, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Republic of Korea)
The diffuse phase transition (DPT) characteristics and the associated defect mechanism of Na-doped Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} (PMN) relaxor perovskite were studied. The enhanced DPT and the decrease in the intensity of the superlattice reflection were observed in the presence of Na{sub 2}O. These contradictory observations were interpreted in terms of the inhibition of the growth of the 1:1 nonstoichiometric short-range ordered domains and the increase in the microcompositional fluctuation of the B-site cations caused by the formation of negatively charged Na{sub Mg}{sup {prime}} sites. The mechanism of the associated defect process was then elucidated by analyzing the electrical conductivity as a function of the oxygen partial pressure. It was shown that the substitution of Na{sup +} ions for Mg{sup 2+} ions in the B-site sublattice of perovskite PMN produced the negatively charged Na{sub Mg}{sup {prime}} sites with a concomitant generation of oxygen vacancies (V{sub O}{sup ..}) for the ionic compensation. This expedites the enhancement of the compositional inhomogeneities of the B-site cations and suppresses the growth of the nonstoichiometrically ordered nanodomains in a disordered matrix. {copyright} {ital 1997 Materials Research Society.}
- OSTI ID:
- 508986
- Journal Information:
- Journal of Materials Research, Vol. 12, Issue 6; Other Information: PBD: Jun 1997
- Country of Publication:
- United States
- Language:
- English
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