Z-contrast imaging of ordered structures in Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} and Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}
- Oak Ridge National Lab., TN (United States). Solid State Div.
- Univ. of Illinois, Urbana, IL (United States). Dept. of Materials Science and Engineering
Lead-based cubic perovskites such as Pb(B{sub 1/3}{sup 2+}B{sub 2/3}{sup 5+})O{sub 3} (B{sup 2+} = Mg, Co, Ni, Zn; B{sup 5+} = Nb, Ta) are relaxor ferroelectrics. Localized order and disorder often occur in materials of this type. In the Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} (PMN) family, previous studies have proposed two models, space-charge and charge-balance models. In the first model, the ordered regions carry a net negative charge [Pb(Mg{sub 1/2}Nb{sub 1/2})O{sub 3}], while in the second model it does not carry a net charge [Pb((Mg{sub 2/3}Nb{sub 1/3}){sub 1/2}Nb{sub 1/2})O{sub 3}]. However, no direct evidence for these two models has appeared in the literature yet. In this paper the authors report the first direct observations of local ordering in undoped and La-doped Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}, using high-resolution Z-contrast imaging. Because the ordered structure in Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} is well known, the Z-contrast image from an ordered domain is used as a reference for this study.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 672115
- Report Number(s):
- ORNL/CP-96681; CONF-980713-; ON: DE98005589; BR: KC0202040; TRN: 99:000594
- Resource Relation:
- Conference: Microscopy and microanalysis 1998, Atlanta, GA (United States), 12-16 Jul 1998; Other Information: PBD: Feb 1998
- Country of Publication:
- United States
- Language:
- English
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