A dual space refinement of short and intermediate range atomic structure in the relaxor ferroelectric Pb(Mg$\sb{1/3}$Nb$\sb{2/3}$)O$\sb3$
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
Political Science, Public Administration|Engineering, Materials Science
Recommended Citation
Henry David Rosenfeld,
"A dual space refinement of short and intermediate range atomic structure in the relaxor ferroelectric Pb(Mg$\sb{1/3}$Nb$\sb{2/3}$)O$\sb3$"
(January 1, 1993).
Dissertations available from ProQuest.
Paper AAI9413898.
http://repository.upenn.edu/dissertations/AAI9413898