title: Total scattering and pair distribution function analysis in modelling disorder in PZN (PbZn1/3Nb2/3O3).
abstract: The ability of the pair distribution function (PDF) analysis of total scattering (TS) from a powder to determine the local ordering in ferroelectric PZN (PbZn1/3Nb2/3O3) has been explored by comparison with a model established using single-crystal diffuse scattering (SCDS). While X-ray PDF analysis is discussed, the focus is on neutron diffraction results because of the greater extent of the data and the sensitivity of the neutron to oxygen atoms, the behaviour of which is important in PZN. The PDF was shown to be sensitive to many effects not apparent in the average crystal structure, including variations in the B-site-O separation distances and the fact that 〈110〉 Pb(2+) displacements are most likely. A qualitative comparison between SCDS and the PDF shows that some features apparent in SCDS were not apparent in the PDF. These tended to pertain to short-range correlations in the structure, rather than to interatomic separations. For example, in SCDS the short-range alternation of the B-site cations was quite apparent in diffuse scattering at (½ ½ ½), whereas it was not apparent in the PDF.
authors: Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia; Neutron Data Analysis and Visualization, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors: Ross E
authors: RE
authors: Whitfield
authors: Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia; School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra, ACT 2600, Australia.
authors: Darren J
authors: DJ
authors: Goossens
authors: Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia.
authors: T Richard
authors: TR
authors: Welberry
keywords: PZN; modelling disorder; pair distribution function analysis; single-crystal diffuse scattering; total scattering