Pyrochlore complex oxides (A2B2O7) are an important class of fluorite-derivative ceramics with exceptional chemical and structural versatility which make them ideal model systems for studying disordering mechanisms over a range of spatial scales. Here, neutron total scattering methods were used to analyze the structural behavior in the non-stoichiometric series NdxZr1-xO2-0.5x (0.5 ≤ x ≤ 0.23) as a function of Nd content, x. Characterization of the structure functions using Rietveld refinement and the pair distribution functions with small-box refinement reveal complex disordering pathways; the average, long-range phase changes over a very narrow compositional range from pyrochlore ($$Fd\bar{3}m$$) to defect fluorite ($$Fm\bar{3}m$$) through full randomization of the cation and anion sublattices at x ~ 0.31, while the local, short-range structure continuously adopts a weberite-type atomic arrangement (C2221). Comparison to a previously studied Ho2Ti2-xZrxO7 solid solution series reveals how changes in chemical composition and stoichiometry modify defect formation and determine how disordering progresses across different length scales in pyrochlore oxides.
Drey, Devon, et al. "Local ordering in disordered Nd<sub>x</sub>Zr<sub>1-x</sub>O<sub>2-0.5x</sub> pyrochlore as observed using neutron total scattering." Acta Materialia, vol. 225, Dec. 2021. https://doi.org/10.1016/j.actamat.2021.117590
Drey, Devon, O'Quinn, Eric, Finkeldei, Sarah, et al., "Local ordering in disordered Nd<sub>x</sub>Zr<sub>1-x</sub>O<sub>2-0.5x</sub> pyrochlore as observed using neutron total scattering," Acta Materialia 225 (2021), https://doi.org/10.1016/j.actamat.2021.117590
@article{osti_1846455,
author = {Drey, Devon and O'Quinn, Eric and Finkeldei, Sarah and Neuefeind, Joerg and Lang, Maik},
title = {Local ordering in disordered Nd<sub>x</sub>Zr<sub>1-x</sub>O<sub>2-0.5x</sub> pyrochlore as observed using neutron total scattering},
annote = {Pyrochlore complex oxides (A2B2O7) are an important class of fluorite-derivative ceramics with exceptional chemical and structural versatility which make them ideal model systems for studying disordering mechanisms over a range of spatial scales. Here, neutron total scattering methods were used to analyze the structural behavior in the non-stoichiometric series NdxZr1-xO2-0.5x (0.5 ≤ x ≤ 0.23) as a function of Nd content, x. Characterization of the structure functions using Rietveld refinement and the pair distribution functions with small-box refinement reveal complex disordering pathways; the average, long-range phase changes over a very narrow compositional range from pyrochlore ($Fd\bar{3}m$) to defect fluorite ($Fm\bar{3}m$) through full randomization of the cation and anion sublattices at x ~ 0.31, while the local, short-range structure continuously adopts a weberite-type atomic arrangement (C2221). Comparison to a previously studied Ho2Ti2-xZrxO7 solid solution series reveals how changes in chemical composition and stoichiometry modify defect formation and determine how disordering progresses across different length scales in pyrochlore oxides.},
doi = {10.1016/j.actamat.2021.117590},
url = {https://www.osti.gov/biblio/1846455},
journal = {Acta Materialia},
issn = {ISSN 1359-6454},
volume = {225},
place = {United States},
publisher = {Elsevier},
year = {2021},
month = {12}}