A dual space refinement of short and intermediate range atomic structure in the relaxor ferroelectric lead(magnesium(1/3)niobium(2/3))oxide

Henry David Rosenfeld, University of Pennsylvania

Abstract

We have obtained a detailed model of short and intermediate range atomic structure in the relaxor ferroelectric Pb(Mg$\sb{1/3}$Nb$\sb{2/3})$O$\sb3$ (PMN). This model was developed using a dual space refinement technique, exploiting both crystallographic (reciprocal space) analysis and pair-distribution function (real space) analysis of atomic structure. The model structure shows the existence of two structurally different regions. In one region two different oxygen octahedral environments about the B cations form an Fm3m superstructure. In the other, displacements of B cations from the ideal cubic perovskite lattice site are correlated such that the B cation sublattice is nearly cubic. Polar micro-regions of 10A to 16A in size with a net polarization in agreement with experimental measurements of RMS polarization are found in both regions. These structural features may explain the diffuse paraelectric/ferroelectric transition and strong dielectric dispersion observed in PMN. The model structure may also explain observed electron diffraction patterns and high resolution transmission electron microscopy images of PMN.

Subject Area

Materials science|Public administration

Recommended Citation

Rosenfeld, Henry David, "A dual space refinement of short and intermediate range atomic structure in the relaxor ferroelectric lead(magnesium(1/3)niobium(2/3))oxide" (1993). Dissertations available from ProQuest. AAI9413898.
https://repository.upenn.edu/dissertations/AAI9413898

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