Display options
Cite
Scavini M, Coduri M, Allieta M, et al. Percolating hierarchical defect structures drive phase transformation in Ce1-x Gd x O2-x/2: a total scattering study. IUCrJ. 2015;2:511-22doi: 10.1107/S2052252515011641.
Scavini, M., Coduri, M., Allieta, M., Masala, P., Cappelli, S., Oliva, C., Brunelli, M., Orsini, F., & Ferrero, C. (2015). Percolating hierarchical defect structures drive phase transformation in Ce1-x Gd x O2-x/2: a total scattering study. IUCrJ, 2511-22. https://doi.org/10.1107/S2052252515011641
Scavini, Marco, et al. "Percolating hierarchical defect structures drive phase transformation in Ce1-x Gd x O2-x/2: a total scattering study." IUCrJ vol. 2 (2015): 511-22. doi: https://doi.org/10.1107/S2052252515011641
Scavini M, Coduri M, Allieta M, Masala P, Cappelli S, Oliva C, Brunelli M, Orsini F, Ferrero C. Percolating hierarchical defect structures drive phase transformation in Ce1-x Gd x O2-x/2: a total scattering study. IUCrJ. 2015 Jul 30;2:511-22. doi: 10.1107/S2052252515011641. eCollection 2015 Sep 01. PMID: 26306193; PMCID: PMC4547819.
Copy Download .nbib Format: NLM
Share it on

IUCrJ. 2015 Jul 30;2:511-22. doi: 10.1107/S2052252515011641. eCollection 2015 Sep 01.

Percolating hierarchical defect structures drive phase transformation in Ce1-x Gd x O2-x/2: a total scattering study.

IUCrJ

Marco Scavini, Mauro Coduri, Mattia Allieta, Paolo Masala, Serena Cappelli, Cesare Oliva, Michela Brunelli, Francesco Orsini, Claudio Ferrero

Affiliations

  1. Dipartimento di Chimica, Università di Milano, via C. Golgi 19, Milano I-20133, Italy ; Istituto di Scienze e Tecnologie Molecolari, CNR-ISTM, Milano I-20133, Italy.
  2. Dipartimento di Chimica, Università di Milano, via C. Golgi 19, Milano I-20133, Italy ; Istituto per l'Energia e le Interfasi, CNR-IENI, C.so Promessi Sposi 29, Lecco I-23900, Italy.
  3. Dipartimento di Chimica, Università di Milano, via C. Golgi 19, Milano I-20133, Italy.
  4. SNBL/ESRF, 71 Avenue des Martyrs, CS 40220, Grenoble Cedex 9, 38043, France.
  5. Dipartimento di Fisica, Università di Milano, Via G. Celoria 19, Milano I-20133, Italy.
  6. ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, Grenoble Cedex 9, 38043, France.

PMID: 26306193 PMCID: PMC4547819 DOI: 10.1107/S2052252515011641

Abstract

A new hierarchical approach is presented for elucidating the structural disorder in Ce1-x Gd x O2-x/2 solid solutions on different scale lengths. The primary goal of this investigation is to shed light on the relations between the short-range and the average structure of these materials via an analysis of disorder on the mesocopic scale. Real-space (pair distribution function) and reciprocal-space (Rietveld refinement and microstructure probing) analysis of X-ray powder diffraction data and electron spin resonance (ESR) investigations were carried out following this approach. On the local scale, Gd- and Ce-rich droplets (i.e. small regions a few ångströms wide) form, exhibiting either a distorted fluorite (CeO2) or a C-type (Gd2O3) structure in the whole compositional range. These droplets can then form C-type nanodomains which, for Gd concentrations x Gd ≤ 0.25, are embedded in the fluorite matrix. At the site percolation threshold p C for a cubic lattice (x Gd = p C ≃ 0.311), C-type nanodomains percolate inside each crystallite and a structural phase transformation is observed. When this occurs, the peak-to-peak ESR line width ΔH pp shows a step-like behaviour, which can be associated with the increase in Gd-Gd dipolar interactions. A general crystallographic rationale is presented to explain the fluorite-to-C-type phase transformation. The approach shown here could be adopted more generally in the analysis of disorder in other highly doped materials.

Keywords: disorder; doped ceria; electron spin resonance; hierarchy; high-resolution X-ray powder diffraction; pair distribution function; percolation; solid electrolytes

References

  1. Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Apr;67(4 Pt 2):046119 - PubMed
  2. J Magn Reson. 2004 Jun;168(2):284-7 - PubMed
  3. J Phys Condens Matter. 2007 Aug 22;19(33):335219 - PubMed
  4. Phys Chem Chem Phys. 2013 Jun 14;15(22):8495-505 - PubMed
  5. Phys Chem Chem Phys. 2014 May 14;16(18):8320-31 - PubMed
  6. Inorg Chem. 2014 Oct 6;53(19):10140-9 - PubMed
  7. J Res Natl Inst Stand Technol. 2004 Feb 01;109(1):133-42 - PubMed

Publication Types