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Title: Electron paramagnetic resonance and Raman spectroscopy studies on carbon-doped MgB{sub 2} superconductor nanomaterials

Undoped and carbon-doped magnesium diboride (MgB{sub 2}) samples were synthesized using two sets of mixtures prepared from the precursors, amorphous nanoboron, and as-received amorphous carbon-doped nanoboron. The microscopic defect structures of carbon-doped MgB{sub 2} samples were systematically investigated using X-ray powder diffraction, Raman and electron paramagnetic resonance spectroscopy. Mg vacancies and C-related dangling-bond active centers could be distinguished, and sp{sup 3}-hybridized carbon radicals were detected. A strong reduction in the critical temperature T{sub c} was observed due to defects and crystal distortion. The symmetry effect of the latter is also reflected on the vibrational modes in the Raman spectra.
Authors:
;  [1] ; ; ;  [2] ; ;  [3] ;  [4]
  1. Department of Chemistry, Koc University, RumelifeneriYolu, Sariyer, Istanbul (Turkey)
  2. Institut für Physikalische Chemie, Universität Freiburg, Albertstr. 21, 79104 Freiburg (Germany)
  3. Pavezyum Kimya Sanayi Dış Ticaret LTD. ŞTI., Tuzla, Istanbul (Turkey)
  4. Leibniz Institute for Solid State and Materials Research Dresden (IFW), P.O. Box 270116, 01171 Dresden (Germany)
Publication Date:
OSTI Identifier:
22402867
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 15; Other Information: (c) 2015 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; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION SPECTRA; CARBON; CRITICAL TEMPERATURE; CRYSTALS; DOPED MATERIALS; ELECTRON SPIN RESONANCE; MAGNESIUM BORIDES; NANOMATERIALS; RAMAN SPECTRA; RAMAN SPECTROSCOPY; TYPE-II SUPERCONDUCTORS; VACANCIES; X-RAY DIFFRACTION