title: Investigating the order-disorder phase transition in Nd2-xYxZr2O7via diffraction and spectroscopy.
abstract: The pyrochlore-defect fluorite phase transition in the mixed-metal zirconate Nd2-xYxZr2O7 (0 ≤ x ≤ 2) solid solution was investigated using synchrotron X-ray and neutron diffraction, as well as X-ray absorption spectroscopy. Diffraction analysis revealed a two-phase region between 1.0 ≤ x ≤ 1.2. In the pyrochlore phase, Zr L3-edge XANES analysis demonstrated a gradual change in the local coordination environment of the B site with increasing Y content that was consistent with an increase in disorder. Although Y L3-edge XANES analysis suggested that the Y cations remained in an ordered coordination environment in the pyrochlore phase, disorder did gradually increase once the fluorite phase formed. It was found that Y cations prefer an ordered coordination environment near the phase boundary whereas Zr cations prefer a disordered coordination environment.
authors.affiliation: School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia. B.Kennedy@chem.usyd.edu.au.
authors.forename: Peter E R
authors.initials: PE
authors.lastname: Blanchard
authors.forename: Samuel
authors.initials: S
authors.lastname: Liu
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: Kennedy
authors.forename: Chris D
authors.initials: CD
authors.lastname: Ling
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Zhang
authors.forename: Maxim
authors.initials: M
authors.lastname: Avdeev
authors.forename: Bruce C C
authors.initials: BC
authors.lastname: Cowie
authors.forename: Lars
authors.initials: L
authors.lastname: Thomsen
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Jang