ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Nonstoichiometric ordering of magnesium and niobium cations in undoped and lanthanum-doped lead magnesium niobate solid solutions has been investigated by means of high-resolution transmission electron microscopy and computer image simulation. High-resolution lattice images were obtained using different objective apertures for various microscope imaging conditions. Computer image simulations were performed for a wide range of sample thicknesses, defocusing conditions, local Mg/Nb ratios, and long-range order parameters. The simulated images demonstrated that the lattice images of the ordered region are predominantly dependent on the long-range order parameter. By a comparison of the experimental and simulated images, a range of values of the long-range order parameter 0.2⩽S〈0.8 was obtained for the ordered regions. It was also shown that the ordered structure has a (NH4)3FeF6 structure, which consists of alternating magnesium- and niobium-preferred sublattices along the 〈111〉 directions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00975076
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