Local Structures of Oxygen-Deficient Perovskite Sr2ScGaO5 Polymorphs Explored by Total Neutron Scattering and EXAFS Spectroscopy
- 6 July 2020
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 59 (13), 9434-9442
- https://doi.org/10.1021/acs.inorgchem.0c01368
Abstract
Depending on the synthesis route, the oxygen ion electrolyte Sr2ScGaO5 shows two polymorphs, a brownmillerite and a cubic perovskite framework. In order to better explore oxygen diffusion pathways and mechanisms, we report here on a multitechnical approach to characterize local structural changes for Sr2ScGaO5 polymorphs as a function of temperature, using a neutron pair distribution function (PDF) analysis together with an extended X-ray absorption fine structure (EXAFS) analysis. While for the brownmillerite type structure PDF and Rietveld refinements yield identical structural descriptions, considerable differences are found for the cubic oxygen-deficient polymorph. On a local scale a brownmillerite type vacancy structure could be evidenced for the cubic phase, suggesting a complex short-range ordering and respective microstructure. Both PDF and EXAFS data confirm an octahedral and tetrahedral coordination for Sc and Ga, respectively, at a local scale for both polymorphs. Related changes in the bond distances and oxygen vacancy ordering are discussed.This publication has 29 references indexed in Scilit:
- Identifying the local structural units in La0.5Ba0.5MnO2.5 and BaY0.25Fe0.75O2.5 through the neutron pair distribution functionDalton Transactions, 2016
- Enhancing Perovskite Electrocatalysis through Strain Tuning of the Oxygen DeficiencyJournal of the American Chemical Society, 2016
- Oxygen-deficient BaTiO3− perovskite as an efficient bifunctional oxygen electrocatalystNano Energy, 2015
- Giant room-temperature magnetodielectric coupling in spark plasma sintered brownmillerite ceramicsApplied Physics Letters, 2014
- Synthesis and Structural Characterization of La1−xAxMnO2.5 (A = Ba, Sr, Ca) Phases: Mapping the Variants of the Brownmillerite StructureChemistry of Materials, 2009
- Synthesis and crystal structure of the Sr2Al1.07Mn0.93O5brownmilleriteJournal of Materials Chemistry, 2006
- Ionic conductivity of brownmillerite-type calcium ferrite under oxidizing conditionsSolid State Ionics, 2006
- Ordering of tetrahedral chains in the Sr2MnGaO5 brownmilleriteJournal of Solid State Chemistry, 2003
- Synthesis, Crystal Structure, and Magnetic Properties of a Novel Layered Manganese Oxide Sr2MnGaO5+δJournal of Solid State Chemistry, 2001
- Oxide-ion conduction in Ba2In2O5 and Ba3In2MO8 (M=Ce, Hf, or Zr)Solid State Ionics, 1990