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Title: Interstitial Fe in MgO

Isolated {sup 57}Fe atoms were studied in MgO single-crystals by emission Mössbauer spectroscopy following implantation of {sup 57}Mn decaying to {sup 57}Fe. Four Mössbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. Two components represent Fe atoms substituting Mg as Fe{sup 2+} and Fe{sup 3+}, respectively; a third component is due to Fe in a strongly implantation-induced disturbed region. The fourth component, which is the focus of this paper, can be assigned to Fe at an interstitial site. Comparison of its measured isomer shift with ab initio calculations suggests that the interstitial Fe is located on, or close to, the face of the rock-salt MgO structure. To harmonize such an assignment with the measured near-zero quadrupole interaction a local motion process (cage motion) of the Fe has to be stipulated. The relation of such a local motion as a starting point for long range diffusion is discussed.
Authors:
; ;  [1] ;  [2] ; ; ;  [3] ; ;  [4] ;  [5] ;  [2] ;  [6] ;  [7] ;  [8] ;  [9]
  1. Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavík (Iceland)
  2. Laboratorio MDM, IMM-CNR, Via Olivetti 2, 20846 Agrate Brianza (MB) (Italy)
  3. Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)
  4. School of Physics, University of the Witwatersrand, WITS 2050 (South Africa)
  5. Durban University of Technology, Durban 4001 (South Africa)
  6. (Italy)
  7. PH Department, ISOLDE/CERN, 1211 Geneva 23 (Switzerland)
  8. Instituut voor Kern-en Stralings fysika, University of Leuven, B-3001 Leuven (Belgium)
  9. Helmholtz-Zentrum-Berlin für Materialien und Energie, D-14109 Berlin (Germany)
Publication Date:
OSTI Identifier:
22271263
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTROSCOPY; CHARGE STATES; COMPARATIVE EVALUATIONS; DIFFUSION; INTERSTITIALS; ION IMPLANTATION; IRON; IRON 57; IRON IONS; ISOMER SHIFT; MAGNESIUM OXIDES; MANGANESE 57; MOESSBAUER EFFECT; MONOCRYSTALS