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Title: Study of Eu{sup 3+} → Eu{sup 2+} reduction in BaAl{sub 2}O{sub 4}:Eu prepared in different gas atmospheres

Highlights: • The effect of different gas atmospheres on the Eu reduction process was studied. • The Eu reduction was monitored analyzing XANES region at the Eu L{sub III}-edge. • Hydrogen reducing agent are the most appropriate gas for Eu{sup 2+} stabilization. • Only a part of the Eu ions can be stabilized in the divalent state. • A model of Eu reduction process is proposed. - Abstract: The effect of different gas atmospheres such as H{sub 2}(g), synthetic air, carbon monoxide (CO) and nitrogen (N{sub 2}) on the Eu{sup 3+} → Eu{sup 2+} reduction process during the synthesis of Eu-doped BaAl{sub 2}O{sub 4} was studied using synchrotron radiation. The Eu{sup 3+} → Eu{sup 2+} reduction was monitored analyzing XANES region when the sample are excited at the Eu L{sub III}-edge. The results show that the hydrogen reducing agent are the most appropriate gas for Eu{sup 2+} stabilization in BaAl{sub 2}O{sub 4} and that only a part of the Eu ions can be stabilized in the divalent state. A model of Eu reduction process, based on the incorporation of charge compensation defects, is proposed.
Authors:
 [1] ;  [2] ;  [3]
  1. Departamento de Física, Universidade Federal de Sergipe, Campus Universitário, 49100-000 Itabaiana-SE (Brazil)
  2. Departamento de Física, Universidade Federal de Sergipe, Campus Universitário, 49100-000 São Cristovão-SE (Brazil)
  3. School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom)
Publication Date:
OSTI Identifier:
22420773
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 61; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ALUMINATES; BARIUM COMPOUNDS; CARBON MONOXIDE; DOPED MATERIALS; EUROPIUM IONS; FINE STRUCTURE; HYDROGEN; NITROGEN; OPTICAL PROPERTIES; REDUCING AGENTS; REDUCTION; STABILIZATION; SYNCHROTRON RADIATION; SYNTHESIS; X-RAY SPECTROSCOPY